安卓作业—-慕课移动应用开发作业22之ContentProvider，ContentResolver与SqliteOpenHelper简单应用移动开发baidu41860619的博客-

本篇做了一个ContentProvider、ContentResolver、SqliteOpenHelper的简单应用，通过ContentProvider提供数据，通过ContentPResolver读取数据。
同时这也是中国大学慕课移动终端应用开发的网课作业22

原题目要求：
（1）创建2个项目，一个ProviderApp用于提供数据，一个ResoverApp用于使用数据，数据源使用SQLite数据库。
（2）自定义ContentProvider。
（3）自定义SQLiteOpenHelper，创建数据库与表。
（4）对数据库的增、删、改、查操作。

说明

1.两个应用，ProviderApp提供数据，ResoverApp使用数据。
2.由于时间问题，我没有做一些判错处理，测试的时候尽量跟随提示输入，进行正确操作，错误的操作如查询为空的时候会闪退。
3.修改数据功能是根据id进行修改的
3.有关ContentProvider方面知识，我建议大家结合网课和此篇博客学习。

演示视频

由于gif图片大小有限制，我只演示部分功能

目录结构

ProviderApp

ResoverApp

代码部分

ProviderApp

1.配置文件 AndroidManifest.xml

添加如下部分

 <provider android:name=".provider.WordContentProvider" android:authorities="com.example.providerapp.WordContentProvider" android:enabled="true" android:exported="true"></provider> 

2.WordCursorWrapper.java

public class WordCursorWrapper extends CursorWrapper { /**      * Creates a cursor wrapper.      *      * @param cursor The underlying cursor to wrap.      */ public WordCursorWrapper(Cursor cursor) { super(cursor); } public Word getWord(){ //获取数据 int id = getInt(getColumnIndex(WordDbSchema.WordTable.Columns.ID));         String english = getString(getColumnIndex(WordDbSchema.WordTable.Columns.ENGLISH));         String chinese = getString(getColumnIndex(WordDbSchema.WordTable.Columns.CHINESE));         String description = getString(getColumnIndex(WordDbSchema.WordTable.Columns.DESCRIPTION)); return new Word(id,english,chinese,description); } } 

3.WordDbSchema.java

public class WordDbSchema { public static final class WordTable{ //定义表名 public static final String TABLE_NAME = "words"; //定义数据表字段 public static final class Columns{ public static final String ID = "id"; public static final String ENGLISH = "english"; public static final String CHINESE = "chinese"; public static final String DESCRIPTION = "description"; } } } 

4.WordSqlHelper.java

public class WordSqlHelper extends SQLiteOpenHelper { private static final int VERSION = 1;//定义版本 private static final String DATABASE_NAME = "course22DataBase"; public WordSqlHelper(@Nullable Context context) { super(context, DATABASE_NAME, null, VERSION); } @Override public void onCreate(SQLiteDatabase db) {         db.execSQL("create table "+ WordDbSchema.WordTable.TABLE_NAME+ "("+"id integer primary key autoincrement,"+                 WordDbSchema.WordTable.Columns.ENGLISH+","+                 WordDbSchema.WordTable.Columns.CHINESE+","+                 WordDbSchema.WordTable.Columns.DESCRIPTION+ ")" ); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { //不更新 } } 

5.Word.java

public class Word { private int id; private String english; private String chinese; private String description; public Word() { } public Word(int id, String english, String chinese, String description) { this.id = id; this.english = english; this.chinese = chinese; this.description = description; } public Word(String english, String chinese, String description) { this.english = english; this.chinese = chinese; this.description = description; } public int getId() { return id; } public void setId(int id) { this.id = id; } @Override public String toString() { return "单词ID:" + id + " 英文:" + english + " 中文:" + chinese + " 描述:" + description; } public String getEnglish() { return english; } public void setEnglish(String english) { this.english = english; } public String getChinese() { return chinese; } public void setChinese(String chinese) { this.chinese = chinese; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } } 

6.WordContentProvider.java

public class WordContentProvider extends ContentProvider { private Context mContext; private SQLiteDatabase mDatabase; //创建authority,授权 public static final String AUTHORITY = "com.example.providerapp.WordContentProvider"; //创建UriMatcher对象 private static UriMatcher sUriMatcher; //静态代码块 static { //实例化UriMatcher对象         sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH); //匹配uri //word是表名         sUriMatcher.addURI(AUTHORITY, "word", 1); //匹配数字         sUriMatcher.addURI(AUTHORITY, "word/#", 2); //匹配文本         sUriMatcher.addURI(AUTHORITY, "word/*", 3); //匹配文本         sUriMatcher.addURI(AUTHORITY, "word/*/*", 4); } @Override public boolean onCreate() { //在这里打开对应数据库         mContext = this.getContext();         mDatabase = new WordSqlHelper(mContext).getWritableDatabase(); return true; } public WordContentProvider() { } /**      * 这里提供了三种删除方式，通过id，通过名字，啥也没有就是全删除      * */ @Override public int delete(Uri uri, String selection, String[] selectionArgs) { int code = sUriMatcher.match(uri); int result = 0; switch (code){ case UriMatcher.NO_MATCH: break; case 1://删除表中所有记录                result = mDatabase.delete(WordDbSchema.WordTable.TABLE_NAME,null,null); break; case 2://投机取巧了一下                // 按id删除                result = mDatabase.delete(WordDbSchema.WordTable.TABLE_NAME,WordDbSchema.WordTable.Columns.ID+" = ? ", new String[]{ContentUris.parseId(uri) + ""}); break; case 3: //按english删除                result = mDatabase.delete(WordDbSchema.WordTable.TABLE_NAME,WordDbSchema.WordTable.Columns.ENGLISH+" = ? ", new String[]{uri.getPathSegments().get(1)}); break; } return result; } @Override public String getType(Uri uri) { // TODO: Implement this to handle requests for the MIME type of the data // at the given URI. throw new UnsupportedOperationException("Not yet implemented"); } /**      * 插入数据，数据一开始就得values      * */ @Override public Uri insert(Uri uri, ContentValues values) { int code = sUriMatcher.match(uri);         Uri result = null; switch (code){ case 1://插入                 long index = mDatabase.insert(WordDbSchema.WordTable.TABLE_NAME,null,values); if (index > 0){ //插入成功,在前面已经有的uri后面追加index                     result = ContentUris.withAppendedId(uri,index); //通知数据已经发生改变 getContext().getContentResolver().notifyChange(result,null); return result; } break; } return null; } /**      * 查找单词信息      * */ @Override public Cursor query(Uri uri, String[] projection, String selection,                         String[] selectionArgs, String sortOrder) { int code = sUriMatcher.match(uri);         Cursor result = null; switch (code){ case 1://查询所有记录                 result = mDatabase.query(WordDbSchema.WordTable.TABLE_NAME,                         projection,selection,selectionArgs,null,null,sortOrder); break; case 2://根据id查询记录                 result = mDatabase.query(WordDbSchema.WordTable.TABLE_NAME,                         projection,WordDbSchema.WordTable.Columns.ID+" = ? ", new String[]{ ContentUris.parseId(uri) + "" },null,null,sortOrder); break; case 3://根据English字段查询                 result = mDatabase.query(WordDbSchema.WordTable.TABLE_NAME,                         projection,WordDbSchema.WordTable.Columns.ENGLISH + " = ? ", new String[]{uri.getPathSegments().get(1)},null,null,sortOrder); break; //            case 4://根据指定的字段名查询记录,第一个是字段名，第二个是参数 //                result = mDatabase.query(WordDbSchema.WordTable.TABLE_NAME, //                        projection,uri.getPathSegments().get(1) + " = ? ", //                        new String[]{uri.getPathSegments().get(2)},null,null,sortOrder); //                break; } return result; } @Override public int update(Uri uri, ContentValues values, String selection,                       String[] selectionArgs) { int code = sUriMatcher.match(uri); int result = 0; switch (code) { case 2://根据指定id更新记录                 result = mDatabase.update(WordDbSchema.WordTable.TABLE_NAME,values,                         WordDbSchema.WordTable.Columns.ID+" = ? ",new String[]{ContentUris.parseId(uri) + ""}); } return result; } //私有方法，返回一个ContentValues对象 private ContentValues getContentValues(Word word){         ContentValues values = new ContentValues(); //添加键值对         values.put(WordDbSchema.WordTable.Columns.ENGLISH,word.getEnglish());         values.put(WordDbSchema.WordTable.Columns.CHINESE,word.getChinese());         values.put(WordDbSchema.WordTable.Columns.DESCRIPTION,word.getDescription()); return values; } } 

7.MainActivity.java

public class MainActivity extends AppCompatActivity { private Button mButton; private TextView mTextView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);          mButton = findViewById(R.id.update);         mTextView = findViewById(R.id.show); /**          * 简单更新数据          * */         mButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //此uri用于查询所有word                 Uri uri = Uri.parse("content://com.example.providerapp.WordContentProvider/word");                 ContentResolver contentResolver = getContentResolver();                 Cursor cursor = contentResolver.query(uri, new String[]{WordDbSchema.WordTable.Columns.ID,                                 WordDbSchema.WordTable.Columns.ENGLISH,                                 WordDbSchema.WordTable.Columns.CHINESE,                                 WordDbSchema.WordTable.Columns.DESCRIPTION,}, null, null, null);                  ArrayList<Word> words = getWords(cursor);                 mTextView.setText(getString(words)); } }); } /**      * 获取arrayList对象      * */ private ArrayList<Word> getWords(Cursor cursor){         ArrayList<Word> words = new ArrayList<>();         WordCursorWrapper wrapper = new WordCursorWrapper(cursor); try {             wrapper.moveToFirst(); while (!wrapper.isAfterLast()){                 words.add(wrapper.getWord());                 wrapper.moveToNext(); } } finally {             wrapper.close(); } return words; } /**      * 将列表展开成字符串      * */ private String getString(ArrayList<Word> words){         String res = ""; for (Word word:words){             res += word.toString()+"n"; } return res; } } 

8.activity_main.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <TextView android:id="@+id/show" android:textSize="20dp" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1"/> <Button android:layout_gravity="bottom" android:id="@+id/update" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="更新数据"/> </LinearLayout> 

ResoverApp

1.WordCursorWrapper.java

public class WordCursorWrapper extends CursorWrapper { /**      * Creates a cursor wrapper.      *      * @param cursor The underlying cursor to wrap.      */ public WordCursorWrapper(Cursor cursor) { super(cursor); } public Word getWord(){ //获取数据 int id = getInt(getColumnIndex(WordDbSchema.WordTable.Columns.ID));         String english = getString(getColumnIndex(WordDbSchema.WordTable.Columns.ENGLISH));         String chinese = getString(getColumnIndex(WordDbSchema.WordTable.Columns.CHINESE));         String description = getString(getColumnIndex(WordDbSchema.WordTable.Columns.DESCRIPTION)); return new Word(id,english,chinese,description); } } 

2.WordDbSchema.java

public class WordDbSchema { public static final class WordTable{ //定义表名 public static final String TABLE_NAME = "words"; //定义数据表字段 public static final class Columns{ public static final String ID = "id"; public static final String ENGLISH = "english"; public static final String CHINESE = "chinese"; public static final String DESCRIPTION = "description"; } } } 

3.Word.java

public class Word { private int id; private String english; private String chinese; private String description; public Word() { } public Word(int id, String english, String chinese, String description) { this.id = id; this.english = english; this.chinese = chinese; this.description = description; } public Word(String english, String chinese, String description) { this.english = english; this.chinese = chinese; this.description = description; } public int getId() { return id; } public void setId(int id) { this.id = id; } @Override public String toString() { return "单词ID:" + id + " 英文:" + english + " 中文:" + chinese + " 描述:" + description; } public String getEnglish() { return english; } public void setEnglish(String english) { this.english = english; } public String getChinese() { return chinese; } public void setChinese(String chinese) { this.chinese = chinese; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } } 

4.MainActivity.java

public class MainActivity extends AppCompatActivity { private EditText mEditTextID,mEditTextEnglish,mEditTextChinese,mEditTextDescription; private Button mButtonAdd,mButtonUpdate,mButtonDeleteAll,mButtonDeleteByEnglish,mButtonDeleteByID,     mButtonFindAll,mButtonFindByEnglish,mButtonFindByID; private TextView mTextView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView();          mButtonAdd.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) {                 String english = mEditTextEnglish.getText().toString();                 String chinese = mEditTextChinese.getText().toString();                 String description = mEditTextDescription.getText().toString();                  ContentValues values = new ContentValues();                 values.put("english",english);                 values.put("chinese",chinese);                 values.put("description",description);                  Uri uri = Uri.parse("content://com.example.providerapp.WordContentProvider/word");                 ContentResolver contentResolver = getContentResolver();                  Uri result = contentResolver.insert(uri,values); if(result!=null){                     Toast.makeText(MainActivity.this, "插入成功！",Toast.LENGTH_LONG).show(); }else {                     Toast.makeText(MainActivity.this,"插入失败！",                             Toast.LENGTH_LONG).show(); } cleanEditText(); } });          mButtonDeleteAll.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) {                 Uri uri = Uri.parse("content://com.example.providerapp.WordContentProvider/word");                 ContentResolver contentResolver = getContentResolver(); int result = contentResolver.delete(uri,null,null); if (result > 0){                     Toast.makeText(MainActivity.this, "删除成功！",Toast.LENGTH_LONG).show(); }else {                     Toast.makeText(MainActivity.this, "删除失败！",Toast.LENGTH_LONG).show(); } cleanEditText(); } });          mButtonDeleteByID.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int id = Integer.parseInt(mEditTextID.getText().toString());                  Uri uri = Uri.parse("content://com.example.providerapp.WordContentProvider/word/"+id);                 ContentResolver contentResolver = getContentResolver(); int result = contentResolver.delete(uri,null,null); if (result > 0){                     Toast.makeText(MainActivity.this, "删除成功！",Toast.LENGTH_LONG).show(); }else {                     Toast.makeText(MainActivity.this, "删除失败！",Toast.LENGTH_LONG).show(); } cleanEditText(); } });          mButtonDeleteByEnglish.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) {                 String english = mEditTextEnglish.getText().toString();                  Uri uri = Uri.parse("content://com.example.providerapp.WordContentProvider/word/"+english);                 ContentResolver contentResolver = getContentResolver(); int result = contentResolver.delete(uri,null,null); if (result > 0){                     Toast.makeText(MainActivity.this, "删除成功！",Toast.LENGTH_LONG).show(); }else {                     Toast.makeText(MainActivity.this, "删除失败！",Toast.LENGTH_LONG).show(); } cleanEditText(); } });          mButtonUpdate.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) {                 String english = mEditTextEnglish.getText().toString();                 String chinese = mEditTextChinese.getText().toString();                 String description = mEditTextDescription.getText().toString();                  ContentValues values = new ContentValues();                 values.put(WordDbSchema.WordTable.Columns.ENGLISH,english);                 values.put(WordDbSchema.WordTable.Columns.CHINESE,chinese);                 values.put(WordDbSchema.WordTable.Columns.DESCRIPTION,description);                  String id = mEditTextID.getText().toString();                  Uri uri = Uri.parse("content://com.example.providerapp.WordContentProvider/word/"+id);                 ContentResolver contentResolver = getContentResolver(); int result = contentResolver.update(uri,values,null,null); if (result > 0){                     Toast.makeText(MainActivity.this, "更新成功！",Toast.LENGTH_LONG).show(); }else {                     Toast.makeText(MainActivity.this, "更新失败！",Toast.LENGTH_LONG).show(); } cleanEditText(); } });          mButtonFindAll.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //此uri用于查询所有word                 Uri uri = Uri.parse("content://com.example.providerapp.WordContentProvider/word");                 ContentResolver contentResolver = getContentResolver();                 Cursor cursor = contentResolver.query(uri, new String[]{WordDbSchema.WordTable.Columns.ID,                                 WordDbSchema.WordTable.Columns.ENGLISH,                                 WordDbSchema.WordTable.Columns.CHINESE,                                 WordDbSchema.WordTable.Columns.DESCRIPTION,}, null, null, null);                  ArrayList<Word> words = getWords(cursor);                 mTextView.setText(getString(words)); cleanEditText(); } });          mButtonFindByEnglish.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) {                 String english = mEditTextEnglish.getText().toString();                  Uri uri = Uri.parse("content://com.example.providerapp.WordContentProvider/word/"+english);                 ContentResolver contentResolver = getContentResolver();                  Cursor cursor = contentResolver.query(uri, new String[]{WordDbSchema.WordTable.Columns.ID,                                 WordDbSchema.WordTable.Columns.ENGLISH,                                 WordDbSchema.WordTable.Columns.CHINESE,                                 WordDbSchema.WordTable.Columns.DESCRIPTION,}, null, null, null);                  ArrayList<Word> words = getWords(cursor);                 mTextView.setText(getString(words)); cleanEditText(); } });          mButtonFindByID.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int id = Integer.parseInt(mEditTextID.getText().toString());                  Uri uri = Uri.parse("content://com.example.providerapp.WordContentProvider/word/"+id);                 ContentResolver contentResolver = getContentResolver();                  Cursor cursor = contentResolver.query(uri, new String[]{WordDbSchema.WordTable.Columns.ID,                                 WordDbSchema.WordTable.Columns.ENGLISH,                                 WordDbSchema.WordTable.Columns.CHINESE,                                 WordDbSchema.WordTable.Columns.DESCRIPTION,}, null, null, null);                  ArrayList<Word> words = getWords(cursor);                 mTextView.setText(getString(words)); cleanEditText(); } }); } /**      * 获取arrayList对象      * */ private ArrayList<Word> getWords(Cursor cursor){         ArrayList<Word> words = new ArrayList<>();         WordCursorWrapper wrapper = new WordCursorWrapper(cursor); try {             wrapper.moveToFirst(); while (!wrapper.isAfterLast()){                 words.add(wrapper.getWord());                 wrapper.moveToNext(); } } finally {             wrapper.close(); } return words; } /**      * 将列表展开成字符串      * */ private String getString(ArrayList<Word> words){         String res = ""; for (Word word:words){             res += word.toString()+"n"; } return res; } private void cleanEditText(){         mEditTextID.setText("");         mEditTextChinese.setText("");         mEditTextEnglish.setText("");         mEditTextDescription.setText(""); } private void initView(){         mEditTextID = findViewById(R.id.edit_id);         mEditTextEnglish = findViewById(R.id.edit_english);         mEditTextChinese = findViewById(R.id.edit_chinese);         mEditTextDescription = findViewById(R.id.edit_description);          mButtonAdd = findViewById(R.id.button_add);         mButtonUpdate = findViewById(R.id.button_update);          mButtonDeleteAll = findViewById(R.id.button_delete_all);         mButtonDeleteByEnglish = findViewById(R.id.button_delete_by_english);         mButtonDeleteByID = findViewById(R.id.button_delete_by_id);          mButtonFindAll = findViewById(R.id.button_find_all);         mButtonFindByEnglish = findViewById(R.id.button_find_by_english);         mButtonFindByID = findViewById(R.id.button_find_by_id);          mTextView = findViewById(R.id.show); } } 

5.activity_main.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <RelativeLayout android:layout_width="match_parent" android:layout_height="150dp" android:background="#CFE7FA"> <LinearLayout android:layout_centerInParent="true" android:layout_width="300dp" android:layout_height="match_parent" android:orientation="vertical"> <LinearLayout android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1"> <TextView android:text="英文:" android:layout_marginLeft="10dp" android:layout_gravity="center" android:layout_width="wrap_content" android:layout_height="wrap_content"/> <EditText android:id="@+id/edit_english" android:layout_width="0dp" android:layout_weight="1" android:layout_height="match_parent" android:textSize="12dp" android:hint="添加或按英文查找、删除时填写"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1"> <TextView android:text="中文:" android:layout_marginLeft="10dp" android:layout_gravity="center" android:layout_width="wrap_content" android:layout_height="wrap_content"/> <EditText android:id="@+id/edit_chinese" android:layout_width="0dp" android:layout_weight="1" android:layout_height="match_parent" android:textSize="12dp" android:hint="添加数据时填写"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1"> <TextView android:text="描述:" android:layout_marginLeft="10dp" android:layout_gravity="center" android:layout_width="wrap_content" android:layout_height="wrap_content"/> <EditText android:id="@+id/edit_description" android:layout_width="0dp" android:layout_weight="1" android:layout_height="match_parent" android:textSize="12dp" android:hint="添加数据时填写"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1"> <TextView android:text=" I D :" android:layout_marginLeft="10dp" android:layout_gravity="center" android:layout_width="wrap_content" android:layout_height="wrap_content"/> <EditText android:id="@+id/edit_id" android:layout_width="0dp" android:layout_weight="1" android:layout_height="match_parent" android:textSize="12dp" android:hint="按ID查询、修改、删除时填写"/> </LinearLayout> </LinearLayout> </RelativeLayout> <TextView android:id="@+id/show" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1"/> <LinearLayout android:layout_width="match_parent" android:layout_height="200dp" android:orientation="vertical"> <LinearLayout android:layout_width="match_parent" android:layout_marginTop="10dp" android:layout_height="0dp" android:layout_weight="1"> <Button android:id="@+id/button_add" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#BDF8F8" android:text="添加数据" android:layout_marginLeft="5dp" android:layout_marginRight="5dp"/> </LinearLayout> <LinearLayout android:layout_marginTop="10dp" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1"> <Button android:id="@+id/button_delete_all" android:text="全部删除" android:layout_marginLeft="5dp" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="3" android:background="#ECF0DD"/> <Button android:id="@+id/button_delete_by_id" android:text="按ID删除" android:layout_marginLeft="10dp" android:layout_marginRight="10dp" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="3" android:background="#ECF0DD"/> <Button android:id="@+id/button_delete_by_english" android:text="按英文删除" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="3" android:background="#ECF0DD" android:layout_marginRight="5dp"/> </LinearLayout> <LinearLayout android:layout_marginTop="10dp" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" > <Button android:id="@+id/button_update" android:background="#D4F5C1" android:layout_width="match_parent" android:layout_height="match_parent" android:text="修改数据" android:layout_marginLeft="5dp" android:layout_marginRight="5dp"/> </LinearLayout> <LinearLayout android:layout_marginTop="10dp" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" > <Button android:id="@+id/button_find_all" android:text="查询全部" android:layout_marginLeft="5dp" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="3" android:background="#EEE0F1" /> <Button android:id="@+id/button_find_by_id" android:text="按ID查询" android:layout_marginLeft="10dp" android:layout_marginRight="10dp" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="3" android:background="#EEE0F1"/> <Button android:id="@+id/button_find_by_english" android:text="按英文查询" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="3" android:background="#EEE0F1" android:layout_marginRight="5dp"/> </LinearLayout> </LinearLayout> </LinearLayout> 

总结

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