AlterDialog对话框的使用

第一步先写出layout文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

   <TextView
       android:id="@+id/tv"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:gravity="center"
       android:text="单选对话框"
       android:layout_marginTop="10dp"
       android:textSize="20sp"
       android:textColor="#fffdb371"/>

    <Button
        android:id="@+id/bt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="设置字体大小"
        android:layout_marginTop="20dp"
        android:layout_gravity="center"/>


</LinearLayout>

第二步写MainActity

package com.iang.dialongdemo;

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.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {


    private TextView textView;
    private int[] textSizeArr={10,20,25,30,40};
    int textSize=1;
//    加载资源文件，找到资源文件中的按钮id号
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.linear);
        findViewById(R.id.bt).setOnClickListener(this);
        textView=(TextView) findViewById(R.id.tv);
    }

    @Override
    public void onClick(View v) {
        AlertDialog dialog;
        AlertDialog.Builder builder=new AlertDialog.Builder(this)
                .setTitle("设置字体大小")
                .setIcon(R.mipmap.ic_launcher)
                .setSingleChoiceItems(new String[]{"小号", "默认", "中号", "大号", "超大"}, textSize, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        textSize=which;
                    }
                })
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        textView.setTextSize(textSizeArr[textSize]);
                        dialog.dismiss();
                    }
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });
        dialog = builder.create();
        dialog.show();
    }
//   回退程序的使用
    @Override
    public void onBackPressed() {
       // super.onBackPressed();
        AlertDialog dialog;
        AlertDialog.Builder builder =new AlertDialog.Builder(this)
                .setTitle("普通对话框")    //设置对话框的标题
                .setIcon(R.mipmap.ic_launcher)   //设置标题图标
                .setMessage("是否确定退出应用:")
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                        MainActivity.this.finish();
                    }
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });
        dialog = builder.create();
        dialog.show();
    }
}

 第三步完成