Android开发中的小技术

1.WebView加载各种类型的网页

?

//打开本包内asset目录下的index.html文件

wView.loadUrl(" file:///android_asset/index.html "); 

 

//打开本地sd卡内的index.html文件

wView.loadUrl("content://com.android.htmlfileprovider/sdcard/index.html");

 

//打开指定URL的html文件

wView.loadUrl(" http://m.oschina.net");

 

2.在一个应用程序中启动另外一个应用程序

?

Intent intent = new Intent(Intent.ACTION_MAIN);

intent.addCategory(Intent.CATEGORY_LAUNCHER);           

ComponentName cn = new ComponentName("com.android.androidweb", "com.android.androidweb.AndroidWeb"); //前面是包名，后面是主类名        

intent.setComponent(cn);

startActivity(intent);

下面记录一个很特殊的，是系统自带的相册程序：

?

Intent intent = new Intent(Intent.ACTION_MAIN);

intent.addCategory(Intent.CATEGORY_LAUNCHER);           

ComponentName cn = new ComponentName("com.android.gallery", "com.android.camera.GalleryPicker");           

intent.setComponent(cn);

startActivity(intent);

知道包名获取启动类的方法：

?

PackageManager pm = getPackageManager();

PackageInfo pi;

try {

    pi = pm.getPackageInfo("com.android.androidweb", 0);//此处加入包名~

    Intent resolveIntent = new Intent(Intent.ACTION_MAIN, null);

    resolveIntent.addCategory(Intent.CATEGORY_LAUNCHER);

    resolveIntent.setPackage(pi.packageName);

 

    List<ResolveInfo> apps = pm.queryIntentActivities(resolveIntent, 0);

 

    ResolveInfo ri = apps.iterator().next();

    if (ri != null ) {

    　　String packageName = ri.activityInfo.packageName;

    　　String className = ri.activityInfo.name;

 

    　　Intent intent = new Intent(Intent.ACTION_MAIN);

    　　intent.addCategory(Intent.CATEGORY_LAUNCHER);

 

    　　ComponentName cn = new ComponentName(packageName, className);

 

    　　intent.setComponent(cn);

    　　startActivity(intent);

    　　}

    } catch (NameNotFoundException e) {

    　　// TODO Auto-generated catch block

    　　e.printStackTrace();

    }