1.Client端代码编写

1.1activity_content_write.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical"

    android:padding="5dp">

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="40dp"

        android:orientation="horizontal">

        <TextView

            android:layout_width="wrap_content"

            android:layout_height="match_parent"

            android:gravity="center"

            android:text="姓名："

            android:textColor="@color/black"

            android:textSize="17sp" />

        <EditText

            android:id="@+id/et_name"

            android:layout_width="0dp"

            android:layout_height="match_parent"

            android:layout_marginTop="3dp"

            android:layout_marginBottom="3dp"

            android:layout_weight="1"

            android:background="@drawable/editext_selector"

            android:hint="请输入姓名"

            android:inputType="text"

            android:maxLength="12"

            android:text="Jack"

            android:textColor="@color/black"

            android:textSize="17sp" />

    </LinearLayout>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="40dp"

        android:orientation="horizontal">

        <TextView

            android:id="@+id/tv_age"

            android:layout_width="wrap_content"

            android:layout_height="match_parent"

            android:gravity="center"

            android:text="年龄："

            android:textColor="@color/black"

            android:textSize="17sp" />

        <EditText

            android:id="@+id/et_age"

            android:layout_width="0dp"

            android:layout_height="match_parent"

            android:layout_marginTop="3dp"

            android:layout_marginBottom="3dp"

            android:layout_weight="1"

            android:background="@drawable/editext_selector"

            android:hint="请输入年龄"

            android:inputType="number"

            android:maxLength="2"

            android:text="18"

            android:textColor="@color/black"

            android:textSize="17sp" />

    </LinearLayout>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="40dp"

        android:orientation="horizontal">

        <TextView

            android:id="@+id/tv_height"

            android:layout_width="wrap_content"

            android:layout_height="match_parent"

            android:gravity="center"

            android:text="身高："

            android:textColor="@color/black"

            android:textSize="17sp" />

        <EditText

            android:id="@+id/et_height"

            android:layout_width="0dp"

            android:layout_height="match_parent"

            android:layout_marginTop="3dp"

            android:layout_marginBottom="3dp"

            android:layout_weight="1"

            android:background="@drawable/editext_selector"

            android:hint="请输入身高"

            android:inputType="number"

            android:maxLength="3"

            android:text="180"

            android:textColor="@color/black"

            android:textSize="17sp" />

    </LinearLayout>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="40dp"

        android:orientation="horizontal">

        <TextView

            android:id="@+id/tv_weight"

            android:layout_width="wrap_content"

            android:layout_height="match_parent"

            android:gravity="center"

            android:text="体重："

            android:textColor="@color/black"

            android:textSize="17sp" />

        <EditText

            android:id="@+id/et_weight"

            android:layout_width="0dp"

            android:layout_height="match_parent"

            android:layout_marginTop="3dp"

            android:layout_marginBottom="3dp"

            android:layout_weight="1"

            android:background="@drawable/editext_selector"

            android:hint="请输入体重"

            android:inputType="numberDecimal"

            android:maxLength="5"

            android:text="180"

            android:textColor="@color/black"

            android:textSize="17sp" />

    </LinearLayout>

    <CheckBox

        android:id="@+id/ck_married"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:checked="false"

        android:gravity="center"

        android:text="已婚"

        android:textColor="@color/black"

        android:textSize="17sp" />

    <Button

        android:id="@+id/btn_save"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="保存"

        android:textColor="@color/black"

        android:textSize="17sp" />

    <Button

        android:id="@+id/btn_read"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="读取"

        android:textColor="@color/black"

        android:textSize="17sp" />

    <Button

        android:id="@+id/btn_delete"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="删除"

        android:textColor="@color/black"

        android:textSize="17sp" />

</LinearLayout>

1.2ContentWriteActivity.java

package com.example.chapter07_client;

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;

import android.content.ContentValues;

import android.database.Cursor;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.widget.CheckBox;

import android.widget.EditText;

import com.example.chapter07_client.entity.User;

import com.example.chapter07_client.util.ToastUtil;

public class ContentWriteActivity extends AppCompatActivity implements View.OnClickListener{

    private EditText et_name;

    private EditText et_age;

    private EditText et_height;

    private EditText et_weight;

    private CheckBox ck_married;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_content_write);

        et_name = findViewById(R.id.et_name);

        et_age = findViewById(R.id.et_age);

        et_height = findViewById(R.id.et_height);

        et_weight = findViewById(R.id.et_weight);

        ck_married = findViewById(R.id.ck_married);

        findViewById(R.id.btn_save).setOnClickListener(this);

        findViewById(R.id.btn_delete).setOnClickListener(this);

        findViewById(R.id.btn_read).setOnClickListener(this);

    }

    @SuppressLint("Range")

    @Override

    public void onClick(View v) {

        switch(v.getId()) {

            case R.id.btn_save:

                ContentValues values = new ContentValues();

                values.put(UserInfoContent.USER_NAME, et_name.getText().toString());

                values.put(UserInfoContent.USER_AGE, Integer.parseInt(et_age.getText().toString()));

                values.put(UserInfoContent.USER_HEIGHT, Integer.parseInt(et_height.getText().toString()));

                values.put(UserInfoContent.USER_WEIGHT, Float.parseFloat(et_weight.getText().toString()));

                values.put(UserInfoContent.USER_MARRIED, ck_married.isChecked());

                getContentResolver().insert(UserInfoContent.CONTENT_URI, values);

                ToastUtil.show(this, "保存成功");

                break;

            case R.id.btn_read:

                Cursor cursor = getContentResolver().query(UserInfoContent.CONTENT_URI, null, null, null, null);

                if (cursor != null) {

                    while(cursor.moveToNext()) {

                        User info = new User();

                        info.id = cursor.getInt(cursor.getColumnIndex(UserInfoContent._ID));

                        info.name = cursor.getString(cursor.getColumnIndex(UserInfoContent.USER_NAME));

                        info.age = cursor.getInt(cursor.getColumnIndex(UserInfoContent.USER_AGE));

                        info.height = cursor.getInt(cursor.getColumnIndex(UserInfoContent.USER_HEIGHT));

                        info.weight = cursor.getFloat(cursor.getColumnIndex(UserInfoContent.USER_WEIGHT));

                        info.married = cursor.getInt(cursor.getColumnIndex(UserInfoContent.USER_MARRIED)) == 1 ? true : false;

                        Log.d("ning", info.toString());

                    }

                    cursor.close();

                }

                break;

        }

    }

}

1.3UserInfoContent.java

package com.example.chapter07_client;

import android.net.Uri;

import android.provider.BaseColumns;

public class UserInfoContent implements BaseColumns {

    public static final String AUTHORITIES = "com.example.chapter07_server.provider.UserInfoProvider";

    // content://com.example.chapter07_server.provider.UserInfoProvider

    // 访问内容提供器的URI

    public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITIES + "/user");

    // 下面是该表的各个字段名称

    public static final String USER_NAME = "name";

    public static final String USER_AGE = "age";

    public static final String USER_HEIGHT = "height";

    public static final String USER_WEIGHT = "weight";

    public static final String USER_MARRIED = "married";

}

1.4效果：

先启动server端：

控制台输出：

D/ning: UserInfoProvider onCreate

再启动client：

点“保存”：

控制台输出：

D/ning: UserInfoProvider insert

再点“读取”： 控制台输出：

D/ning: UserInfoProvider query

D/ning: User{id=1, name='Jack', age=18, height=180, weight=180.0, married=false}

再点击“保存”、“读取”，控制台输出：

D/ning: UserInfoProvider query

D/ning: User{id=1, name='Jack', age=18, height=180, weight=180.0, married=false}

D/ning: User{id=2, name='Jack', age=18, height=180, weight=180.0, married=false}

2.数据删除

2.1chapter07-server应用的UserInfoProvider.java新增内容：



private static final UriMatcher URI_MATCHER = new UriMatcher(UriMatcher.NO_MATCH);

private static final int USERS = 1;
private static final int USER = 2;

static {
    // 往Uri匹配器中添加指定的数据路径
    URI_MATCHER.addURI(UserInfoContent.AUTHORITIES, "/user", USERS);
    URI_MATCHER.addURI(UserInfoContent.AUTHORITIES, "/user/#", USER);
}



// content://com.example.chapter07_server.provider.UserInfoProvider/user
@Override
public Uri insert(Uri uri, ContentValues values) {
    Log.d("ning", "UserInfoProvider insert");
    if (URI_MATCHER.match(uri) == USERS) {
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        db.insert(UserDBHelper.TABLE_NAME, null, values);
    }
    return uri;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
                    String[] selectionArgs, String sortOrder) {
    Log.d("ning", "UserInfoProvider query");
    if (URI_MATCHER.match(uri) == USERS) {
        SQLiteDatabase db = dbHelper.getReadableDatabase();
        return db.query(UserDBHelper.TABLE_NAME, projection, selection, selectionArgs, null, null, null);
    }
    return null;
}

@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
    int count = 0;
    switch (URI_MATCHER.match(uri)) {
        // content://com.example.chapter07_server.provider.UserInfoProvider/user
        // 删除多行
        case USERS:
            SQLiteDatabase db1 = dbHelper.getWritableDatabase();
            count = db1.delete(UserDBHelper.TABLE_NAME, selection, selectionArgs);
            db1.close();
            break;
        // content://com.example.chapter07_server.provider.UserInfoProvider/user/2
        // 删除单行
        case USER:
            String id = uri.getLastPathSegment();
            SQLiteDatabase db2 = dbHelper.getWritableDatabase();
            count = db2.delete(UserDBHelper.TABLE_NAME, "_id=?", new String[]{id});
            db2.close();
            break;
    }

    return count;
}




2.2charpter07-client应用的清单文件，新增内容：




<!-- 出于安全考虑，Android 11 要求应用事先说明需要访问的其他软件包 -->

    <queries>

        <package android:name="com.example.chapter07_server"/>

    </queries>




2.3charpter07-client应用的ContentWriteActivity.java中新增内容：




@SuppressLint("Range")

    @Override

    public void onClick(View v) {

        switch(v.getId()) {

            case R.id.btn_save:

                ContentValues values = new ContentValues();

                values.put(UserInfoContent.USER_NAME, et_name.getText().toString());

                values.put(UserInfoContent.USER_AGE, Integer.parseInt(et_age.getText().toString()));

                values.put(UserInfoContent.USER_HEIGHT, Integer.parseInt(et_height.getText().toString()));

                values.put(UserInfoContent.USER_WEIGHT, Float.parseFloat(et_weight.getText().toString()));

                values.put(UserInfoContent.USER_MARRIED, ck_married.isChecked());

                getContentResolver().insert(UserInfoContent.CONTENT_URI, values);

                ToastUtil.show(this, "保存成功");

                break;

            case R.id.btn_read:

                Cursor cursor = getContentResolver().query(UserInfoContent.CONTENT_URI, null, null, null, null);

                if (cursor != null) {

                    while(cursor.moveToNext()) {

                        User info = new User();

                        info.id = cursor.getInt(cursor.getColumnIndex(UserInfoContent._ID));

                        info.name = cursor.getString(cursor.getColumnIndex(UserInfoContent.USER_NAME));

                        info.age = cursor.getInt(cursor.getColumnIndex(UserInfoContent.USER_AGE));

                        info.height = cursor.getInt(cursor.getColumnIndex(UserInfoContent.USER_HEIGHT));

                        info.weight = cursor.getFloat(cursor.getColumnIndex(UserInfoContent.USER_WEIGHT));

                        info.married = cursor.getInt(cursor.getColumnIndex(UserInfoContent.USER_MARRIED)) == 1 ? true : false;

                        Log.d("ning", info.toString());

                    }

                    cursor.close();

                }

                break;

            case R.id.btn_delete:

                // 单行删除：

                // content://com.example.chapter07_server.provider.UserInfoProvider/user/2

//                Uri uri = ContentUris.withAppendedId(UserInfoContent.CONTENT_URI, 10);

//                int count = getContentResolver().delete(uri, null, null);

                // 多行删除：

                // content://com.example.chapter07_server.provider.UserInfoProvider/user

                int count = getContentResolver().delete(UserInfoContent.CONTENT_URI, "name=?", new String[]{"Jack"});

                if (count > 0) {

                    ToastUtil.show(this, "删除成功");

                }

                break;

        }

    }




2.4charpter07-client及charpter07-server应用的UserInfoContent.java新增内容：




public static final String AUTHORITIES = "com.example.chapter07_server.provider.UserInfoProvider";

    // content://com.example.chapter07_server.provider.UserInfoProvider

    // 访问内容提供器的URI

    public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITIES + "/user");




2.5效果：


2.5.1单条删除：


点“读取”：




D/ning: User{id=8, name='Jack', age=18, height=180, weight=180.0, married=false}
D/ning: User{id=9, name='Jack', age=18, height=180, weight=180.0, married=false}
D/ning: User{id=10, name='Jack', age=18, height=180, weight=180.0, married=false}
D/ning: User{id=11, name='Jack', age=18, height=180, weight=180.0, married=false}




点“删除”，删除id=10的，再点“读取”，可以看到id=10的已经被删除了：




D/ning: User{id=8, name='Jack', age=18, height=180, weight=180.0, married=false}
D/ning: User{id=9, name='Jack', age=18, height=180, weight=180.0, married=false}
D/ning: User{id=11, name='Jack', age=18, height=180, weight=180.0, married=false}




2.5.2多条删除：


点“读取”：




D/ning: User{id=8, name='Jack', age=18, height=180, weight=180.0, married=false}

D/ning: User{id=9, name='Jack', age=18, height=180, weight=180.0, married=false}

D/ning: User{id=11, name='Jack', age=18, height=180, weight=180.0, married=false}




点“删除”，删除所有名字等于"Jack"的，再点“读取”，可以看到全都删除了（因为名字都等于Jack）：


（备注：这里直接点“读取”，会报WaitForGcToComplete blocked Instrumentation on None for 6.246ms。所以我采用先点一下“保存”，再点“读取”的方式。查出来id=12，说明点击“删除”时，当时所有name=Jack的记录即id=8,9,11的，已经都被删掉了。）




D/ning: User{id=12, name='Jack', age=18, height=180, weight=180.0, married=false}


												


																

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