Android-Launcher開發之AppWidget(2)

AppWidget 通過內存共享進行數據通訊.原理圖如下:

1.創建一個BroadcastReceiver,繼承AppWidgetProvider.

2.在AndroidManifest.xml中配置如下:下面給出官網例子是必須的.

 

 

3.提供一個標簽裡resource的xml文件,定義appwidget的樣式屬性(配置參數可選)

 

4.定義appwidget的樣式.定義一個layout文件做為布局文件 ,並配置在上面intialLayout屬性中.

 

5.當用戶點擊選取添加某個小部件.首先獲取appWidgetId,並打開一個選取小部件的Activity

6.選取後,通過appWidgetId獲取appWidgetInfo,並轉化為LauncherAppWidgetInfo對象,並添加到workspace中.

當然,這段時間包括了appwidget的定位.其添加源碼如下:

 

 private void completeAddAppWidget(Intent data, CellLayout.CellInfo cellInfo) {
        Bundle extras = data.getExtras();
        int appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, -1);

        if (LOGD) Log.d(TAG, dumping extras content= + extras.toString());

        AppWidgetProviderInfo appWidgetInfo = mAppWidgetManager.getAppWidgetInfo(appWidgetId);

        // Calculate the grid spans needed to fit this widget
        CellLayout layout = (CellLayout) mWorkspace.getChildAt(cellInfo.screen);
        int[] spans = layout.rectToCell(appWidgetInfo.minWidth, appWidgetInfo.minHeight);

        // Try finding open space on Launcher screen
        final int[] xy = mCellCoordinates;
        if (!findSlot(cellInfo, xy, spans[0], spans[1])) {
            if (appWidgetId != -1) mAppWidgetHost.deleteAppWidgetId(appWidgetId);
            return;
        }

        // Build Launcher-specific widget info and save to database
        LauncherAppWidgetInfo launcherInfo = new LauncherAppWidgetInfo(appWidgetId);
        launcherInfo.spanX = spans[0];
        launcherInfo.spanY = spans[1];

        LauncherModel.addItemToDatabase(this, launcherInfo,
                LauncherSettings.Favorites.CONTAINER_DESKTOP,
                mWorkspace.getCurrentScreen(), xy[0], xy[1], false);

        if (!mRestoring) {
            mDesktopItems.add(launcherInfo);

            // Perform actual inflation because we're live
            launcherInfo.hostView = mAppWidgetHost.createView(this, appWidgetId, appWidgetInfo);

            launcherInfo.hostView.setAppWidget(appWidgetId, appWidgetInfo);
            launcherInfo.hostView.setTag(launcherInfo);

            mWorkspace.addInCurrentScreen(launcherInfo.hostView, xy[0], xy[1],
                    launcherInfo.spanX, launcherInfo.spanY, isWorkspaceLocked());
        }
    }

總結:當我們執行完前3步,系統即會根據用戶選擇創建小部件.

--更新AppWidget界面,其原理如下:

 

1AppWidgetManager發送廣播傳遞ID.

 

void updateProvidersForPackageLocked(String pkgName) {
        HashSet keep = new HashSet();
        Intent intent = new Intent(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
        intent.setPackage(pkgName);
        List broadcastReceivers = mPackageManager.queryBroadcastReceivers(intent,
                PackageManager.GET_META_DATA);

        // add the missing ones and collect which ones to keep
        int N = broadcastReceivers == null ? 0 : broadcastReceivers.size();
        for (int i=0; i 0) {
                            int[] appWidgetIds = getAppWidgetIds(p);
                            // Reschedule for the new updatePeriodMillis (don't worry about handling
                            // it specially if updatePeriodMillis didn't change because we just sent
                            // an update, and the next one will be updatePeriodMillis from now).
                            cancelBroadcasts(p);
                            registerForBroadcastsLocked(p, appWidgetIds);
                            // If it's currently showing, call back with the new AppWidgetProviderInfo.
                            for (int j=0; j=0; i--) {
            Provider p = mInstalledProviders.get(i);
            if (pkgName.equals(p.info.provider.getPackageName())
                    && !keep.contains(p.info.provider.getClassName())) {
                removeProviderLocked(i, p);
            }
        }
    }

 

2.用戶自定義AppwidgetProvider的onUpdate()接收數據.並通過Manager更新界面.(如下,官網給出了2個操作,1更新界面 2.點擊小部件操作)

 

public class ExampleAppWidgetProvider extends AppWidgetProvider {

    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        final int N = appWidgetIds.length;

        // Perform this loop procedure for each App Widget that belongs to this provider
        for (int i=0; i
--Updating the App Widget from the configuration Activity(通過配置選項更改APPwidget界面,當Appwidget創建時,先進入該Activity進行判斷)
1.創建Activity並在AndroidManifest.xml裡面配置:
 
         
            
                
            
        
2.在appwidget的配置xml裡面增加屬性:
 
 
android:configure=org.lean.ConfigureActivity


3.在Activity中操作,1>根據配置修改遠程界面,2>跳轉回選擇的activity並由他關閉選擇Activity並顯示Launcher界面
 
 
package org.lean;

import android.app.Activity;
import android.appwidget.AppWidgetManager;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.EditText;
import android.widget.RemoteViews;

/**
 *		
 *
 * 	@author Lean  @date:2014-8-27  
 */
public class ConfigureActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.configure_view);
		findViewById(R.id.button1).setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				int appwidgetId=getIntent().getExtras().getInt(AppWidgetManager.EXTRA_APPWIDGET_ID,AppWidgetManager.INVALID_APPWIDGET_ID);
				if (appwidgetId!=AppWidgetManager.INVALID_APPWIDGET_ID) {
					//修改遠程界面
					EditText editText=(EditText) findViewById(R.id.editText1);
					String currenEtStr=editText.getText().toString();
					RemoteViews views=new RemoteViews(ConfigureActivity.this.getPackageName(),
							R.layout.layout_widget);
					views.setTextViewText(R.id.btn,currenEtStr);
					AppWidgetManager manager=AppWidgetManager.getInstance(ConfigureActivity.this);
					manager.updateAppWidget(appwidgetId, views);
					//返回activity
					
					Intent reIntent=new Intent();
					reIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,appwidgetId);
					setResult(RESULT_OK,reIntent);
					finish();
				}
				
			}
		});
	}
	
}