Android 常用的功能

1、Android返回功能實現

@Override    public boolean onKeyDown(int keyCode, KeyEvent event)    {        if(keyCode == KeyEvent.KEYCODE_BACK){            Intent myIntent = new Intent();            myIntent = new Intent(EditActivity.this, tabActivity.class);            startActivity(myIntent);            this.finish();        }        return super.onKeyDown(keyCode, event);    }

2、Toast顯示訊息

Toast toast = Toast.makeText(getApplicationContext(),     "自訂位置Toast"+checkedId, Toast.LENGTH_LONG);   toast.setGravity(Gravity.CENTER, 0, 0);   toast.show();

3、 RadioGroup

class RadioListener implements OnCheckedChangeListener {@Overridepublic void onCheckedChanged(RadioGroup group, int checkedId) {// TODO Auto-generated method stub if(radioButton1.getId() == checkedId){Toast toast = Toast.makeText(getApplicationContext(),     "自啟動按鈕", Toast.LENGTH_LONG);   toast.setGravity(Gravity.CENTER, 0, 0);   toast.show();}else{Toast toast = Toast.makeText(getApplicationContext(),     "關閉程式", Toast.LENGTH_LONG);   toast.setGravity(Gravity.CENTER, 0, 0);   toast.show();}}}

 4、一個Activity中關閉另一個Activity

    4.1

public class A_activity extends Activity {       public static A_activity instance = null;          @Override          protected void onCreate(Bundle savedInstanceState) {                // TODO Auto-generated method stub                super.onCreate(savedInstanceState);                 .....               instance = this;          }    }   public class B_activity extends Activity {           @Override          protected void onCreate(Bundle savedInstanceState) {                   // TODO Auto-generated method stub                 super.onCreate(savedInstanceState);                 A_activity.instance.finish();           }    }    

     4.2 通過ActivityManager

ActivityManager manager = (ActivityManager)getSystemService(ACTIVITY_SERVICE);   manager.restartPackage(packageName);  

 5.添加菜單

@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// TODO Auto-generated method stubgetMenuInflater().inflate(R.menu.main, menu);return super.onCreateOptionsMenu(menu);}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {// TODO Auto-generated method stubswitch (item.getItemId()) {case R.id.exit:finish();System.exit(0);break;default:break;}return super.onOptionsItemSelected(item);}