Android笔记(七十) AlertDialog

      alertdialog可以在当前界面中弹出一个对话框，这个对话框在界面所有元素之上，可以屏蔽掉其他控件的交互能力，因此alertdialog常用于一些重要的内容警告。

      使用AlertDialog.Builder创建对话框需要了解以下几个方法：

      setTitle ：为对话框设置标题
      setIcon ：为对话框设置图标
      setMessage：为对话框设置内容
      setView ： 给对话框设置自定义样式
      setItems ：设置对话框要显示的一个list，一般用于显示几个命令时
      setMultiChoiceItems ：用来设置对话框显示一系列的复选框
      setNeutralButton    ：普通按钮

      setPositiveButton   ：给对话框添加"Yes"按钮
      setNegativeButton ：对话框添加"No"按钮

      setCancelable：点击其他部位是否可以取消alertdialog，默认为true

      setSingleChoiceItems：设置类似于单选框一样的list
      create ： 创建对话框
      show ：显示对话框

普通的AlertDialog：

package com.example.alertdialogdemo;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private Button bt;
    private TextView tv;
    private Context mContext;

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

        mContext = MainActivity.this;

        bt = (Button) findViewById(R.id.bt);
        tv = (TextView) findViewById(R.id.tv);
        bt.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
                dialog.setCancelable(false);
                dialog.setIcon(R.drawable.remind);
                dialog.setTitle("This is title!");
                dialog.setMessage("This is Message!");
                dialog.setPositiveButton("YES", new OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(mContext, "YES→" + which, Toast.LENGTH_SHORT).show();
                        changeText(which);
                    }
                });
                dialog.setNegativeButton("NO", new OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(mContext, "NO→" + which, Toast.LENGTH_SHORT).show();
                        changeText(which);
                    }
                });

                dialog.show();
            }
        });
    }

    public void changeText(int which) {
        if (which == -1) {
            tv.setText("您选择的是YES！");
        } else if (which == -2) {
            tv.setText("您选择的是NO！");
        }
    }
}

运行结果：

　　

类似ListView的AlertDialog

package com.example.alertdialogdemo;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private Button bt;
    private TextView tv;
    private Context mContext;
    private String[] phones = { "三星", "苹果", "小米", "魅族", "锤子", "华为", "中兴" };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mContext = MainActivity.this;
        bt = (Button) findViewById(R.id.bt);
        tv = (TextView) findViewById(R.id.tv);
        bt.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
                dialog.setCancelable(true);
                dialog.setIcon(R.drawable.phone);
                dialog.setTitle("选择你喜欢的手机");
                dialog.setItems(phones, new OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        changeText(which);
                    }
                });
                dialog.show();
            }
        });
    }

    public void changeText(int which) {
        tv.setText("您选择的手机是： " + phones[which]);
    }
}

运行结果：

单选AlertDialog

package com.example.alertdialogdemo;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private Button bt;
    private TextView tv;
    private Context mContext;
    private String[] sex = { "男生", "女生", "雌雄同体" };

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

        mContext = MainActivity.this;

        bt = (Button) findViewById(R.id.bt);
        tv = (TextView) findViewById(R.id.tv);
        bt.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
                dialog.setCancelable(true);
                dialog.setIcon(R.drawable.phone);
                dialog.setTitle("你的性别：");
                // 第二个参数是默认选择位置
                dialog.setSingleChoiceItems(sex, 0, new OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        changeText(which);
                    }
                });
                dialog.setPositiveButton("OK", new OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                    }
                });
                dialog.show();
            }
        });
    }

    public void changeText(int which) {
        tv.setText("您的性别是： " + sex[which]);
    }
}

运行结果：

多选AlertDialog

package com.example.alertdialogdemo;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.content.DialogInterface.OnMultiChoiceClickListener;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity {

    private Button bt;
    private TextView tv;
    private Context mContext;
    private String[] hobby = { "看电影", "看书", "上网", "篮球", "足球", "游泳", "逛街", "羽毛球" };
    private List<String> hobbyList;

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

        mContext = MainActivity.this;

        hobbyList = new ArrayList<String>();

        bt = (Button) findViewById(R.id.bt);
        tv = (TextView) findViewById(R.id.tv);
        bt.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
                dialog.setCancelable(true);
                dialog.setIcon(R.drawable.heart);
                dialog.setTitle("你的性别：");

                dialog.setMultiChoiceItems(hobby, null, new OnMultiChoiceClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                        hobbyList.add(hobby[which]);

                    }
                });

                dialog.setPositiveButton("OK", new OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        changeText();
                    }
                });
                dialog.show();
            }
        });
    }

    public void changeText(int which) {

    }

    public void changeText() {
        String str = "";

        for (int i = 0; i < hobbyList.size(); i++) {
            str = hobbyList.get(i) + " " + str;
        }

        tv.setText("您的爱好有： " + str);
    }
}

运行结果：

自定义AlertDialog

MainActivity.java

package com.example.alertdialogdemo;

import java.util.ArrayList;
import java.util.List;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

@SuppressLint("NewApi")
public class MainActivity extends Activity {

    private Button bt;
    private TextView tv;
    private Context mContext;
    private View view;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mContext = MainActivity.this;
        bt = (Button) findViewById(R.id.bt);
        tv = (TextView) findViewById(R.id.tv);
        bt.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
                view = LayoutInflater.from(mContext).inflate(R.layout.custom_view_dialog, null);
                dialog.setCancelable(true);
                dialog.setTitle("你的身高：");
                dialog.setView(view);
                dialog.setPositiveButton("OK", new OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        changeText();
                    }
                });
                dialog.show();
            }
        });
    }
    public void changeText() {
        EditText et = (EditText) view.findViewById(R.id.height);
        String height = et.getText().toString().trim();
        tv.setText("身高：" + height + " cm");
    }
}

custom_view_dialog.xml

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

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ruler" />

    <EditText
        android:id="@+id/height"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="cm" />

</LinearLayout>

运行效果：