contentObserver---contentprovider

//如果在AndroidManifest.xml中<provider >不存在的话，在eclipse里面运行这个AP的时候，就会报错，

01-01 21:37:47.617: E/AndroidRuntime(3245): java.lang.RuntimeException: Unable to get provider com.contentp.test3.MyContentProvider: java.lang.ClassNotFoundException: com.contentp.test3.MyContentProvider

依此类推，我认为在AndroidManifest.xml中定义的组件也必须都存在，否则就会出错。

 

ContentObserver学习：

定义一个activity，监听/取消监听某Uri

package com.contentp.test3;

import android.app.Activity;
import android.content.ContentResolver;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.provider.Settings;
import android.util.Log;
//用一个AP访问 系统中存在的联系人AP
public class ContentProviderTest3Activity extends Activity {
    /** Called when the activity is first created. */
    private ContentResolver cr;
    private AirContentObserver aco;
    private String TAG = "ContentProviderTest3Activity";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        aco = new AirContentObserver(mHander);
        regisContentObserver();
    }
    private void regisContentObserver(){
        cr = getContentResolver();
        Uri mUri = Settings.System.getUriFor(Settings.System.AIRPLANE_MODE_ON);
        //注册ContentObserver，别忘了unregister.
        cr.registerContentObserver(mUri, true, aco);
    }
    Handler mHander = new Handler(){

        @Override
        public void handleMessage(Message msg) {
            // TODO Auto-generated method stub
            super.handleMessage(msg);
        }
        
    };
    //别忘了unregister.
    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
        cr.unregisterContentObserver(aco);
        Log.v(TAG,"$$$$onDestroy--unregister");
    }
    
}

 

定义ContentObserver的子类，override onChange()方法

package com.contentp.test3;

import android.database.ContentObserver;
import android.os.Handler;
import android.util.Log;

public class AirContentObserver extends ContentObserver{
    private String TAG = "ContentProviderTest3Activity";
    public AirContentObserver(Handler handler) {
        super(handler);
        // TODO Auto-generated constructor stub
    }
//所有ContentObserver子类都要override此onChange()方法。
    @Override
    public void onChange(boolean selfChange) {
        // TODO Auto-generated method stub
        super.onChange(selfChange);
        Log.v(TAG,"$$$$$onchange");
    }

}

这样，当手机的飞行模式开启或关闭的时候，Uri就会发生变化，ContentObserver的子类的onChange()回调方法就会被调用，就会打出来onChange（）里面的log。

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参考别人的：

 

 

package com.sql.test1;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
//SQLiteOpenHelper是一个abstract class
public class MySqliteHelper extends SQLiteOpenHelper {
    public static final int VERSION=1;
    public static final String TABLE_NAME="srx0209";
    public static final String ID="_id";
    public static final String TEXT="text";
    public static final String DATABASE_NAME="srx.db";
    public MySqliteHelper(Context context){
        super(context, DATABASE_NAME, null, VERSION);
    }
    //数据库第一次生成的时候会调用这个方法，一般我们在这个方法里面生成表
    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        //创建表
    /*    String str_create=//"CREATE TABLE"+TABLE_NAME+"("+ID+"INTEGER PRIMARY KEY AUTOINCREMENT,"+TEXT+"text);";
         "CREATE TABLE " + TABLE_NAME + "(" + ID
          + " INTEGER PRIMARY KEY AUTOINCREMENT," + TEXT
          + " text );";
        db.execSQL(str_create);*/
        Log.d("MySqliteHelper", "MySqliteHelper---onCreate--");
    }
    //插入数据后，数据库立即更新。当数据库需要升级的时候，Android系统会自动（主动）调用此方法
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        Log.d("MySqliteHelper", "$$$$$$$call onUpgrade");
    }

}

 

 

package com.sql.test1;

import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.widget.Button;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;

public class SQLiteTest1Activity extends Activity {
    /** Called when the activity is first created. */
    private static final String TAG = "SQLiteTest1Activity";
    private Button btn_new_table;
    private Button btn_insert;
    private Button btn_delete_record;
    private Button btn_delete_table;
    private Button btn_modify;
    private Button btn_search;
    // 创建一个继承SQLiteOpenHelper的实例
    private MySqliteHelper myOpenHelper;
    private SQLiteDatabase sqDatabase;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn_new_table = (Button) findViewById(R.id.new_table);
        btn_insert = (Button) findViewById(R.id.insert);
        btn_delete_record = (Button) findViewById(R.id.delete_record);
        btn_delete_table = (Button) findViewById(R.id.delete_table);
        btn_modify = (Button) findViewById(R.id.modify);
        btn_search = (Button) findViewById(R.id.search);
        btn_new_table.setOnClickListener(myListener);
        btn_insert.setOnClickListener(myListener);
        btn_delete_record.setOnClickListener(myListener);
        btn_delete_table.setOnClickListener(myListener);
        btn_modify.setOnClickListener(myListener);
        btn_search.setOnClickListener(myListener);
        // 初始化SQLiteOpenHelper的子类的实例，new MySqliteHelper 类实例对象的时候并没有创建数据库！
        myOpenHelper = new MySqliteHelper(this);
        // myOpenHelper.getReadableDatabase();
    }

    OnClickListener myListener = new OnClickListener() {

        public void onClick(View v) {
            // getReadableDatabase：android
            // 会分析是否已经有了数据库，若没有会默认为我们创建一个数据库并且在系统路径data-data-包名下生成XX.db 文件!
            sqDatabase = myOpenHelper.getReadableDatabase();
            // TODO Auto-generated method stub
            if (v.getId() == R.id.new_table) {//若MySqliteHelper已经创建了这个表，故此处按钮可不要，如果再点，会出错，提示表已经存在。
                String TABLE_NAME = "srx0209";
                String ID = "_id";
                String TEXT = "text";
                //ID这一列type是integer，TEXT这一列type是text类型。
                String str_sql2 = "CREATE TABLE " + TABLE_NAME + "(" + ID
                        + " INTEGER PRIMARY KEY AUTOINCREMENT," + TEXT
                        + " text );";
                sqDatabase.execSQL(str_sql2);
                Log.d(TAG, "####new a table");
            } else if (v.getId() == R.id.insert) {
                ContentValues cv = new ContentValues();
                //cv.put(MySqliteHelper.TEXT, "测试新的数据");
                cv.put(MySqliteHelper.TEXT, "testnewdata");
                sqDatabase.insert(MySqliteHelper.TABLE_NAME, null, cv);
                Log.d(TAG, "####insert");
            } else if (v.getId() == R.id.delete_record) {
                sqDatabase.delete(MySqliteHelper.TABLE_NAME, MySqliteHelper.ID + "=1", null);
                Log.d(TAG, "####delete_record");
            } else if (v.getId() == R.id.delete_table) {
                sqDatabase.execSQL("DROP TABLE srx0209");
                Log.d(TAG, "####delete_table");
            } else if (v.getId() == R.id.modify) {
                ContentValues cv = new ContentValues();
                cv.put(MySqliteHelper.TEXT, "修改后的数据");
                sqDatabase.update(MySqliteHelper.TABLE_NAME, cv,
                        "_id " + "=" + Integer.toString(3), null);
                Log.d(TAG, "####modify");
            } else if (v.getId() == R.id.search) {
                Cursor cur = sqDatabase.rawQuery("SELECT * FROM "
                        + MySqliteHelper.TABLE_NAME, null);
                if (cur != null) {
                    String temp = "";
                    int i = 0;
                    while (cur.moveToNext()) {// 直到返回false说明表中到了数据末尾
                        temp += cur.getString(0);
                        // 参数0 指的是列的下标,这里的0指的是id列
                        temp += cur.getString(1);
                        // 这里的0相对于当前应该是咱们的text列了
                        i++;
                        temp += "  "; // 这里是我整理显示格式 ,呵呵~
                        if (i % 3 == 0) // 这里是我整理显示格式 ,呵呵~
                            temp += "\n";// 这里是我整理显示格式 ,呵呵~
                        Log.d(TAG, "temp=="+temp);
                    }
                }
                Log.d(TAG, "####search");
            }
        }

    };
}