Android 代码中实现返回键功能

代码里实现返回键

Runtime

[code]/**
 * Allows Java applications to interface with the environment in which they are running. Applications can not create an instance of this class, but they can get a singleton instance by invoking getRuntime()
  */
      Runtime runtime = Runtime.getRuntime();
      try {
           runtime.exec("input keyevent " + KeyEvent.KEYCODE_BACK);
       } catch (IOException e) {
            e.printStackTrace();
       }

Instrumentation

[code]/**
* Base class for implementing application instrumentation code. When running with instrumentation turned on, this class will be instantiated for you before any of the application code, allowing you to monitor all of the interaction the system has with the application. An Instrumentation implementation is described to the system through an AndroidManifest.xml's <instrumentation> tag.
 */
         new Thread(){
         @Override
         public void run() {
                Instrumentation ins = new Instrumentation();
                ins.sendKeyDownUpSync(KeyEvent.KEYCODE_BACK);
             }
         }.start();

若想在返回的时候干点别的

onKeyDown

[code]@Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            //do something
            return false;
        } else {
            return super.onKeyDown(keyCode, event);
        }
    }