按返回键退出程序

[android]代码库

@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		if(keyCode==KeyEvent.KEYCODE_BACK)
			exitdialog();
		return super.onKeyDown(keyCode, event);
	}

	private void exitdialog() {
		Dialog dialog=new AlertDialog.Builder(类名.this)
		                       .setTitle("退出程序")
		                       .setMessage("你确认要退出本程序吗？")
		                       .setPositiveButton("确定", new OnClickListener() {
								@Override
								public void onClick(DialogInterface dialo, int whicutton) {
									类名.this.finish();
									
								}
							}).setNegativeButton("取消", new OnClickListener() {
								@Override
								public void onClick(DialogInterface dilg, int whchutton) {
									
								}
							}).create();
		dialog.show();
		
	}