关于线程的几点说明和自定义contentprovider实例

 多线程中，线程之间程序空间和数据空间是共享的 （局部变量不共享）。

如下的代码中是测试自定义contentprovider和contentobserver的实例，

在代码中，contentsevice和activity分别在不同的线程中，onchange就是在contentservice的线程中被执行的，而它访问里activity线程中的mhandler数据变量。

 

 

 

 package com.test;

import android.R.bool;
import android.R.integer;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.ContentProvider;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.DialogInterface;
import android.database.ContentObserver;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.Switch;
//import android.widget.Switch;
import android.widget.TextView;
import android.widget.Toast;
/*当开关状体发生发生变化时更新状态，当点击textview是插入一个条目
 * 当数据库发生变化时，observer会在contentservice的线程中被调用onchang（），在onchange中我们通知主线程数据库发生了变化。
 * 主线程的handler主要处理数据库的变化，这里这是简单的打印*/
public class TestContentObserverActivity extends Activity {
    /** Called when the activity is first created. */
	private int num=0;
	private Boolean bool = true;
	private ContentResolver mContentResolver;
	private Handler mHandler = new Handler(){

		/* (non-Javadoc)
		 * @see android.os.Handler#handleMessage(android.os.Message)
		 */
		@Override
		public void handleMessage(Message msg) {
			// TODO Auto-generated method stub
//			super.handleMessage(msg);
			Log.d("", "handle maeesage "+ num+"  "+Thread.currentThread()+"  "+mHandler.getLooper().getThread());
		}
		
	};
	private   ContentObserver contentObserver = new ContentObserver(null) {

		/* (non-Javadoc)
		 * @see android.database.ContentObserver#onChange(boolean)
		 */
		@Override
		public void onChange(boolean selfChange) {
			// TODO Auto-generated method stub
//			super.onChange(selfChange);
			Log.d("", "observer onchang"+ getTaskId()+Thread.currentThread()+"  "+num);
//			mTextView.setText(""+num);  不能再子线程中更新UI
			num = num +1;
			Message msg = new Message();
			mHandler.sendMessage(msg);
			 /*Looper.prepare();  
			 Toast.makeText(getApplicationContext(), "change", Toast.LENGTH_SHORT).show();
             Looper.loop(); 
			子线程中无法获取操作窗口的权限，所以次数不能显示dialog
			final AlertDialog.Builder mBuilder = new AlertDialog.Builder(getApplicationContext());
			mBuilder.setTitle("observer");
			mBuilder.setMessage("good");
			mBuilder.setPositiveButton(((CharSequence)"ok"),  new DialogInterface.OnClickListener() {
				
				@Override
				public void onClick(DialogInterface dialog, int which) {
					// TODO Auto-generated method stub
					mBuilder.create().dismiss();
				}
			});
			mBuilder.setNegativeButton(((CharSequence)"cancel"), new DialogInterface.OnClickListener() {
				
				@Override
				public void onClick(DialogInterface dialog, int which) {
					// TODO Auto-generated method stub
					
					AlertDialog mAlertDialog = mBuilder.create();
				}
			});
			mBuilder.create().show();*/
			
		}
	};
	
	
	
	private Switch mSwitch;
	private TextView mTextView;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
    	
    	Log.d("", "activity create" +getTaskId()+Thread.currentThread());
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       
        mContentResolver = getContentResolver();
        
        mSwitch=(Switch) findViewById(R.id.switch1);
        mTextView= (TextView) findViewById(R.id.text);
        mTextView.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				Log.d("", "onclick "+Thread.currentThread());
				Uri uri = Uri.parse("content://com.test/observer");
				ContentValues values = new ContentValues();
				values.put("status", bool);
				getContentResolver().insert(uri, values);
			}
		});
        
        mSwitch.setOnCheckedChangeListener(new OnCheckedChangeListener() {
			
			@Override
			public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
				// TODO Auto-generated method stub
				
				Log.d("", "onCheckedChanged " +Thread.currentThread());
				Uri uri = Uri.parse("content://com.test/observer");
				ContentValues values = new ContentValues();;
				values.put("status", isChecked);
				String where = "status =?";
				Boolean boo = !isChecked;
				String[] whereArgs = {boo.toString()};
				getContentResolver().update(uri, values, where, whereArgs);
			}
		});
        mContentResolver.registerContentObserver(Uri.parse("content://com.test/observer"), true, contentObserver);
    }
    
    
    
    /* (non-Javadoc)
	 * @see android.app.Activity#onResume()
	 */
	@Override
	protected void onResume() {
		// TODO Auto-generated method stub
		super.onResume();
		Log.d("", "activity resume");
//		ContentValues mValues = new  ContentValues();
//		mValues.put("status", false);
//		mContentResolver.insert(Uri.parse("content://com.test/observer"), mValues);
	}



	public  ContentObserver getContentObserver(){
    	return contentObserver;
    }
    public static TestContentObserverActivity getTestContentObserverActivity(){
    	return new TestContentObserverActivity();
    }
}

 package com.test;

import android.content.ContentProvider;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.ContentObserver;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.net.Uri;
import android.util.Log;

public class MyContentProvider extends ContentProvider{
	
	private static final UriMatcher sURLMatcher = new UriMatcher(
            UriMatcher.NO_MATCH);
   private Boolean bool = true;
    static {
        sURLMatcher.addURI("com.test", "observer", 1);
        sURLMatcher.addURI("com.test", "observer/#", 2);
//        sURLMatcher.addURI("com.test", "location", LOCATIONS);
//        sURLMatcher.addURI("com.test", "apps", APPS);
    }
	
	
//	private ContentObserver contentObserver = TestContentObserverActivity.getTestContentObserverActivity().getContentObserver();
	private SQLiteDatabase mSqLiteDatabase;
	private SQLiteOpenHelper mSqLiteOpenHelper;
		
		public class MySQLiteOpenHelper extends SQLiteOpenHelper{
			
			public MySQLiteOpenHelper(Context context){
				super(context, "mydb.db", null, 6);
			}
			@Override
			public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
				// TODO Auto-generated method stub
				Log.d("", "helper upgrade");
				db.execSQL("drop table if exists observer");
				onCreate(db);
			}
			
			@Override
			public void onCreate(SQLiteDatabase db) {
				// TODO Auto-generated method stub
				Log.d("", "helper create");
				String sql="CREATE TABLE  if not exists observer(_id INTEGER primary key autoincrement, status Boolean)";
				if (db==null)
					Log.d("", "helper create failed");
				db.execSQL(sql);
			}
		}
	

	/* (non-Javadoc)
	 * @see android.content.ContentProvider#onCreate()
	 */
	@Override
	public boolean onCreate() {
		// TODO Auto-generated method stub
		Log.d("", "mycontentprovider create");
		Context context = getContext();
		Log.d("",""+context);
		if (mSqLiteOpenHelper == null)
			mSqLiteOpenHelper = new MySQLiteOpenHelper(context);
		return true;
	}

	/* (non-Javadoc)
	 * @see android.content.ContentProvider#query(android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String)
	 */
	@Override
	public Cursor query(Uri uri, String[] projection, String selection,
			String[] selectionArgs, String sortOrder) {
		// TODO Auto-generated method stub
		return null;
	}

	/* (non-Javadoc)
	 * @see android.content.ContentProvider#insert(android.net.Uri, android.content.ContentValues)
	 */
	@Override
	public Uri insert(Uri uri, ContentValues values) {
		
		Log.d("", "mycontentprovider insert");
		// TODO Auto-generated method stub
		SQLiteDatabase mDatabase = mSqLiteOpenHelper.getWritableDatabase();
		mDatabase.insert("observer", null, values);
		Context context = getContext();
		context.getContentResolver().notifyChange(uri, null);
		return null;
	}

	/* (non-Javadoc)
	 * @see android.content.ContentProvider#update(android.net.Uri, android.content.ContentValues, java.lang.String, java.lang.String[])
	 */
	@Override
	public int update(Uri uri, ContentValues values, String selection,
			String[] selectionArgs) {
		
		Log.d("", "mycontentprovider update");
		// TODO Auto-generated method stub
		SQLiteDatabase mDatabase = mSqLiteOpenHelper.getWritableDatabase();
		mDatabase.update("observer", values, selection, selectionArgs);
		Context context = getContext();
		context.getContentResolver().notifyChange(uri, TestContentObserverActivity.getTestContentObserverActivity().getContentObserver());
		return 1;
	}

	@Override
	public String getType(Uri uri) {
		// TODO Auto-generated method stub
		int match = sURLMatcher.match(uri);
        switch (match) {
            case 1:
                return "vnd.android.cursor.dir/observer";
            case 2:
                return "vnd.android.cursor.item/observer";
            
            default:
                throw new IllegalArgumentException("Unknown URL");
        }
	}

	@Override
	public int delete(Uri uri, String selection, String[] selectionArgs) {
		// TODO Auto-generated method stub
		return 0;
	}
	
}

其他的应用访问数据库：

package com.test1;

import android.R.integer;
import android.app.Activity;
import android.content.ContentResolver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;

public class TestsqlActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        query();
    }
    
    private void query(){
    	Uri uri=Uri.parse("content://com.test/observer");
    	ContentResolver mcr= getContentResolver();
    	Cursor mCursor = mcr.query(uri, new String[]{"_id","status"},null, null, null);
//    	mCursor.moveToFirst();
    	while(mCursor.moveToNext()){
    		Log.d("111111111 ", "_id = "+ mCursor.getColumnIndex("_id")+", status= "+ mCursor.getColumnIndex("status"));
    		int  id = mCursor.getInt(mCursor.getColumnIndex("_id"));
    		int status = mCursor.getInt(mCursor.getColumnIndex("status"));
    		Log.d(" 2222", "_id = "+ id+", status= "+ status);
    		
    		Log.d("3333 ", ""+mCursor);
    	}
    	mCursor.close();
    }
    
    
}