按钮单击事件未执行

Question

我在Activity类的onCreate()方法中编写了以下代码

Button btn=(Button)findViewById(R.id.button1);
        btn.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v) 
            {
                WindowManager.LayoutParams params = getWindow().getAttributes();
                params.screenBrightness = 0;
                getWindow().setAttributes(params);
                Toast.makeText(v.getContext(),"Button Clicked",Toast.LENGTH_LONG).show();
            }
        });
        btn.performClick();

但问题是按钮点击的操作没有发生,但如果我点击该按钮,则执行此操作.

我想通过使用该代码锁定屏幕,但它在完全执行onCreate()方法后锁定,

任何猜测我怎么能做到这一点.

Answer 1

试试这个

final Button backto_main = (Button) findViewById(R.id.back3x3); 
    backto_main.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {                 
            //add your code here..
            WindowManager.LayoutParams params = getWindow().getAttributes();
            params.screenBrightness = 0;
            getWindow().setAttributes(params);
            Toast.makeText(v.getContext(),"Button Clicked",Toast.LENGTH_LONG).show();
        }
    });