ContentProvider将程序中的数据暴露给其他程序访问

之前写过一篇文章，这里写链接内容讲的是如何运用ContentProvider。这次我将来演示一遍如何将程序中的数据暴露给其他程序访问。

就用我之前写过的AccountMS的数据这里写链接内容。现在我在dao目录下增加MyProvider.java文件，代码如下：

package com.example.accountsoft.dao;

import android.content.ContentProvider;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;

public class MyProvider extends ContentProvider {
private DBOpenHelper helper;
private SQLiteDatabase db;

public MyProvider() {
super();
}

@Override
public boolean onCreate() {
return false;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
helper = new DBOpenHelper(getContext());
db = helper.getWritableDatabase();
Cursor cursor = db.query("tb_inaccount", null, null, null, null, null, null, null);
return cursor;
}

@Override
public String getType(Uri uri) {
return null;
}

@Override
public Uri insert(Uri uri, ContentValues values) {
return null;
}

@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
return 0;
}

@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
return 0;
}
}

然后在AndroidManifest.xml需要配置Provider，将自己的数据暴露出来：

<provider
android:name="com.example.accountsoft.dao.MyProvider"
android:exported="true"
android:authorities="com.example.accountsoft.dao.MyProvider">
<!-- exported选项表示是否能够被其他应用调用    -->
</provider>

然后先建一个项目AccountReader来读取数据：

xml里面就一个Button和TextView

MainActivity代码如下：

package com.example.accountreader;

import android.app.Activity;
import android.content.ContentResolver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity {
private Button button;
private TextView content;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

content = (TextView)findViewById(R.id.textView1);

button = (Button)findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
ContentResolver resolver = getContentResolver();

Uri uri = Uri.parse("content://com.example.accountsoft.dao.MyProvider/tb_inaccount");
//content+authorities+table_name
Cursor cursor = resolver.query(uri, null, null, null, null);

StringBuilder stringBuilder = new StringBuilder();
while (cursor != null && cursor.moveToNext()) {
int id = cursor.getInt(cursor.getColumnIndex("_id"));
double money = cursor.getDouble(cursor.getColumnIndex("money"));
stringBuilder.append(id+"+"+money+"\n");
}
content.setText(stringBuilder.toString());
}
});
}
}

展示一下最后的结果：