android开发 点击按钮弹出对话框的简单实现

代码：

package com.example.lenovo.duihuakuang;import android.content.DialogInterface;import android.support.v7.app.AlertDialog;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initEvent();    }    private void initEvent() {        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {            showDialog();            }        });    }    private void showDialog(){        AlertDialog.Builder builder=new AlertDialog.Builder(this);        builder.setIcon(R.drawable.picture);        builder.setTitle("温馨提示");        builder.setMessage("天冷多加衣！");        builder.setPositiveButton("我知道了",                new DialogInterface.OnClickListener() {                    @Override                    public void onClick(DialogInterface dialogInterface, int i) {                    }                });        AlertDialog dialog=builder.create();        dialog.show();        }    }

效果图：