Android 泛型小例 findById

package com.louisgeek.louisgenericstest;

import android.app.Activity;
import android.app.Dialog;
import android.view.View;

/**
* 泛型自动类型自动推导
* 缺点 用的时候需要注意   类型与id类型是否真正对应
* Created by louisgeek on 2016/9/13.
*/
public class ViewTool {
public static <V extends View> V findById(Activity activity, int resID){
return (V) activity.findViewById(resID);
}

public static <V extends View> V findById(View view, int id) {
return (V) view.findViewById(id);
}

public static <V extends View> V findById(Dialog dialog, int id) {
return (V) dialog.findViewById(id);
}
}

package com.louisgeek.louisgenericstest;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

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

TextView textView=ViewTool.findById(this,R.id.id_tv);
textView.setText("zhuzhu");
}
}