Hook技术

public class MainActivity extends AppCompatActivity {

    TextView mTextView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mTextView = findViewById(R.id.text);

        mTextView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.e("tag", "origin click");
            }
        });

        hookOnClickListener(mTextView);

    }

    private void hookOnClickListener(View view) {
        try {
            // 得到 View 的 ListenerInfo 对象
            Method getListenerInfo = View.class.getDeclaredMethod("getListenerInfo");
            getListenerInfo.setAccessible(true);
            Object listenerInfo = getListenerInfo.invoke(view);
            // 得到 原始的 OnClickListener 对象
            Class<?> listenerInfoClz = Class.forName("android.view.View$ListenerInfo");
            Field mOnClickListener = listenerInfoClz.getDeclaredField("mOnClickListener");
            mOnClickListener.setAccessible(true);
            View.OnClickListener originOnClickListener = (View.OnClickListener) mOnClickListener.get(listenerInfo);
            // 用自定义的 OnClickListener 替换原始的 OnClickListener
            View.OnClickListener hookedOnClickListener = new HookedOnClickListener(originOnClickListener);
            mOnClickListener.set(listenerInfo, hookedOnClickListener);
        } catch (Exception e) {
            Log.e("tag", "hook clickListener failed!", e);
        }
    }

    public class HookedOnClickListener implements View.OnClickListener {
        private View.OnClickListener origin;

        HookedOnClickListener(View.OnClickListener origin) {
            this.origin = origin;
        }

        @Override
        public void onClick(View v) {
            Toast.makeText(MainActivity.this, "hook click", Toast.LENGTH_SHORT).show();
            Log.e("tag", "Before click, do what you want to to.");
            if (origin != null) {
                origin.onClick(v);
            }
            Log.e("tag", "After click, do what you want to to.");
        }
    }
}