android基础及基本应用
（一）、Activity
Android中，Activity是所有程序的根本，所有程序的流程都运行在Activity之中，Activity具有自己的生命周期（见http://www.cnblogs.com/feisky/archive/2010/01/01/1637427.html，由系统控制生命周期，程序无法改变，但可以用onSaveInstanceState保存其状态）。
对于Activity，关键是其生命周期的把握（如下图），其次就是状态的保存和恢复（onSaveInstanceState onRestoreInstanceState），以及Activity之间的跳转和数据传输（intent）。
Activity中常用的函数有SetContentView() findViewById() finish() startActivity()，其生命周期涉及的函数有：
void onCreate(Bundle savedInstanceState)void onStart()void onRestart()void onResume()void onPause()void onStop()void onDestroy()
<activity android:name="NotesList" android:label="@string/title_notes_list"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> <intent-filter> <action android:name="android.intent.action.VIEW" /> <action android:name="android.intent.action.EDIT" /> <action android:name="android.intent.action.PICK" /> <category android:name="android.intent.category.DEFAULT" /> <data android:mimeType="vnd.android.cursor.dir/vnd.google.note" /> </intent-filter> <intent-filter> <action android:name="android.intent.action.GET_CONTENT" /> <category android:name="android.intent.category.DEFAULT" /> <data android:mimeType="vnd.android.cursor.item/vnd.google.note" /> </intent-filter> </activity>
Intent it = new Intent(Activity.Main.this, Activity2.class);startActivity(it);
Intent it = new Intent(Activity.Main.this, Activity2.class);Bundle bundle=new Bundle();bundle.putString("name", "This is from MainActivity!");it.putExtras(bundle); // it.putExtra(“test”, "shuju”);startActivity(it); // startActivityForResult(it,REQUEST_CODE);Bundle bundle=getIntent().getExtras();String name=bundle.getString("name");startActivityForResult(it,REQUEST_CODE)启动的Activity） Intent intent=getIntent(); Bundle bundle2=new Bundle(); bundle2.putString("name", "This is from ShowMsg!"); intent.putExtras(bundle2); setResult(RESULT_OK, intent);@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { // TODO Auto-generated method stub super.onActivityResult(requestCode, resultCode, data); if (requestCode==REQUEST_CODE){ if(resultCode==RESULT_CANCELED) setTitle("cancle"); else if (resultCode==RESULT_OK) { String temp=null; Bundle bundle=data.getExtras(); if(bundle!=null) temp=bundle.getString("name"); setTitle(temp); } } }Uri uri = Uri.parse("http://google.com"); Intent it = new Intent(Intent.ACTION_VIEW, uri); startActivity(it);Uri uri = Uri.parse("geo:38.899533,-77.036476"); Intent it = new Intent(Intent.ACTION_VIEW, uri); startActivity(it); //其他 geo URI 範例 //geo:latitude,longitude //geo:latitude,longitude?z=zoom //geo:0,0?q=my+street+address //geo:0,0?q=business+near+city //google.streetview:cbll=lat,lng&cbp=1,yaw,,pitch,zoom&mz=mapZoomUri uri = Uri.parse("http://maps.google.com/maps?f=d&saddr=startLat%20startLng&daddr=endLat%20endLng&hl=en"); Intent it = new Intent(Intent.ACTION_VIEW, uri); startActivity(it); //where startLat, startLng, endLat, endLng are a long with 6 decimals //like:50.123456 Uri uri = Uri.parse("tel:0800000123"); Intent it = new Intent(Intent.ACTION_DIAL, uri); startActivity(it); Uri uri = Uri.parse("tel:0800000123"); Intent it = new Intent(Intent.ACTION_CALL, uri); startActivity(it); //用這個，要在 AndroidManifest.xml 中，加上 //<uses-permission id="android.permission.CALL_PHONE" /> Uri uri = Uri.parse("smsto://0800000123"); Intent it = new Intent(Intent.ACTION_SENDTO, uri); it.putExtra("sms_body", "The SMS text"); startActivity(it); Uri uri = Uri.parse("content://media/external/images/media/23"); Intent it = new Intent(Intent.ACTION_SEND); it.putExtra("sms_body", "some text"); it.putExtra(Intent.EXTRA_STREAM, uri); it.setType("image/png"); startActivity(it); Uri uri = Uri.parse("mailto:xxx@abc.com"); Intent it = new Intent(Intent.ACTION_SENDTO, uri); startActivity(it); Intent it = new Intent(Intent.ACTION_SEND); it.putExtra(Intent.EXTRA_EMAIL, "me@abc.com"); it.putExtra(Intent.EXTRA_TEXT, "The email body text"); it.setType("text/plain"); startActivity(Intent.createChooser(it, "Choose Email Client")); Intent it=new Intent(Intent.ACTION_SEND); String[] tos={"me@abc.com"}; String[] ccs={"you@abc.com"}; it.putExtra(Intent.EXTRA_EMAIL, tos); it.putExtra(Intent.EXTRA_CC, ccs); it.putExtra(Intent.EXTRA_TEXT, "The email body text"); it.putExtra(Intent.EXTRA_SUBJECT, "The email subject text"); it.setType("message/rfc822"); startActivity(Intent.createChooser(it, "Choose Email Client"));Intent it = new Intent(Intent.ACTION_SEND); it.putExtra(Intent.EXTRA_SUBJECT, "The email subject text"); it.putExtra(Intent.EXTRA_STREAM, "file:///sdcard/mysong.mp3"); sendIntent.setType("audio/mp3"); startActivity(Intent.createChooser(it, "Choose Email Client"));Uri uri = Uri.parse("file:///sdcard/song.mp3"); Intent it = new Intent(Intent.ACTION_VIEW, uri); it.setType("audio/mp3"); startActivity(it); Uri uri = Uri.withAppendedPath(MediaStore.Audio.Media.INTERNAL_CONTENT_URI, "1"); Intent it = new Intent(Intent.ACTION_VIEW, uri); startActivity(it);Uri uri = Uri.parse("market://search?q=pname:pkg_name"); Intent it = new Intent(Intent.ACTION_VIEW, uri); startActivity(it); //where pkg_name is the full package path for an application Uri uri = Uri.parse("market://details?id=app_id"); Intent it = new Intent(Intent.ACTION_VIEW, uri); startActivity(it); //where app_id is the application ID, find the ID //by clicking on your application on Market home //page, and notice the ID from the address bar Uri uri = Uri.fromParts("package", strPackageName, null); Intent it = new Intent(Intent.ACTION_DELETE, uri); startActivity(it);