AlertDialog(对话框)

https://www.runoob.com/w3cnote/android-tutorial-seekbar.html

1.基本使用流程

• Step 1：创建AlertDialog.Builder对象；
• Step 2：调用setIcon()设置图标，setTitle()或setCustomTitle()设置标题；
• Step 3：设置对话框的内容：setMessage()还有其他方法来指定显示的内容；
• Step 4：调用setPositive/Negative/NeutralButton()设置：确定，取消，中立按钮；
• Step 5：调用create()方法创建这个对象，再调用show()方法将对话框显示出来；

2.几种常用的对话框使用示例

核心代码：

MainActivity.java：

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private Button btn_dialog_one;
    private Button btn_dialog_two;
    private Button btn_dialog_three;
    private Button btn_dialog_four;

    private Context mContext;
    private boolean[] checkItems;

    private AlertDialog alert = null;
    private AlertDialog.Builder builder = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mContext = MainActivity.this;
        bindView();


    }

    private void bindView() {
        btn_dialog_one = (Button) findViewById(R.id.btn_dialog_one);
        btn_dialog_two = (Button) findViewById(R.id.btn_dialog_two);
        btn_dialog_three = (Button) findViewById(R.id.btn_dialog_three);
        btn_dialog_four = (Button) findViewById(R.id.btn_dialog_four);
        btn_dialog_one.setOnClickListener(this);
        btn_dialog_two.setOnClickListener(this);
        btn_dialog_three.setOnClickListener(this);
        btn_dialog_four.setOnClickListener(this);
    }


    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            //普通对话框
            case R.id.btn_dialog_one:
                alert = null;
                builder = new AlertDialog.Builder(mContext);
                alert = builder.setIcon(R.mipmap.ic_icon_fish)
                        .setTitle("系统提示：")
                        .setMessage("这是一个最普通的AlertDialog,\n带有三个按钮，分别是取消，中立和确定")
                        .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                Toast.makeText(mContext, "你点击了取消按钮~", Toast.LENGTH_SHORT).show();
                            }
                        })
                        .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                Toast.makeText(mContext, "你点击了确定按钮~", Toast.LENGTH_SHORT).show();
                            }
                        })
                        .setNeutralButton("中立", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                Toast.makeText(mContext, "你点击了中立按钮~", Toast.LENGTH_SHORT).show();
                            }
                        }).create();             //创建AlertDialog对象
                alert.show();                    //显示对话框
                break;
            //普通列表对话框
            case R.id.btn_dialog_two:
                final String[] lesson = new String[]{"语文", "数学", "英语", "化学", "生物", "物理", "体育"};
                alert = null;
                builder = new AlertDialog.Builder(mContext);
                alert = builder.setIcon(R.mipmap.ic_icon_fish)
                        .setTitle("选择你喜欢的课程")
                        .setItems(lesson, new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                Toast.makeText(getApplicationContext(), "你选择了" + lesson[which], Toast.LENGTH_SHORT).show();
                            }
                        }).create();
                alert.show();
                break;
            //单选列表对话框
            case R.id.btn_dialog_three:
                final String[] fruits = new String[]{"苹果", "雪梨", "香蕉", "葡萄", "西瓜"};
                alert = null;
                builder = new AlertDialog.Builder(mContext);
                alert = builder.setIcon(R.mipmap.ic_icon_fish)
                        .setTitle("选择你喜欢的水果，只能选一个哦~")
                        .setSingleChoiceItems(fruits, 0, new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                Toast.makeText(getApplicationContext(), "你选择了" + fruits[which], Toast.LENGTH_SHORT).show();
                            }
                        }).create();
                alert.show();
                break;
            //多选列表对话框
            case R.id.btn_dialog_four:
                final String[] menu = new String[]{"水煮豆腐", "萝卜牛腩", "酱油鸡", "胡椒猪肚鸡"};
                //定义一个用来记录个列表项状态的boolean数组
                checkItems = new boolean[]{false, false, false, false};
                alert = null;
                builder = new AlertDialog.Builder(mContext);
                alert = builder.setIcon(R.mipmap.ic_icon_fish)
                        .setMultiChoiceItems(menu, checkItems, new DialogInterface.OnMultiChoiceClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                                checkItems[which] = isChecked;
                            }
                        })
                        .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                String result = "";
                                for (int i = 0; i < checkItems.length; i++) {
                                    if (checkItems[i])
                                        result += menu[i] + " ";
                                }
                                Toast.makeText(getApplicationContext(), "客官你点了:" + result, Toast.LENGTH_SHORT).show();
                            }
                        })
                        .create();
                alert.show();
                break;
        }
    }
}

布局就是四个简单的按钮，这里就不贴出来了，用法非常简单~无非就是创建一个Builder对象后， 进行相关设置，然后create()生成一个AlertDialog对象，最后调用show()方法将AlertDialog 显示出来而已！另外，细心的你可能发现我们点击对话框的外部区域，对话框就会消失，我们 可以为builder设置setCancelable(false)即可解决这个问题！

 

3.通过Builder的setView()定制显示的AlertDialog

 

我们可以自定义一个与系统对话框不同的布局，然后调用setView()将我们的布局加载到 AlertDialog上，上面我们来实现这个效果：

 

关键代码：

首先是两种不同按钮的selctor的drawable文件：

btn_selctor_exit.xml：

btn_selctor_choose.xml：

接着是自定义的Dialog布局：view_dialog_custom.xml：

最后是MainActivity.java：

public class MainActivity extends AppCompatActivity {

    private Button btn_show;
    private View view_custom;
    private Context mContext;
    private AlertDialog alert = null;
    private AlertDialog.Builder builder = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mContext = MainActivity.this;
        btn_show = (Button) findViewById(R.id.btn_show);

        //初始化Builder
        builder = new AlertDialog.Builder(mContext);

        //加载自定义的那个View,同时设置下
        final LayoutInflater inflater = MainActivity.this.getLayoutInflater();
        view_custom = inflater.inflate(R.layout.view_dialog_custom, null,false);
        builder.setView(view_custom);
        builder.setCancelable(false);
        alert = builder.create();

        view_custom.findViewById(R.id.btn_cancle).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                alert.dismiss();
            }
        });

        view_custom.findViewById(R.id.btn_blog).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getApplicationContext(), "访问博客", Toast.LENGTH_SHORT).show();
                Uri uri = Uri.parse("http://blog.csdn.net/coder_pig");
                Intent intent = new Intent(Intent.ACTION_VIEW, uri);
                startActivity(intent);
                alert.dismiss();
            }
        });

        view_custom.findViewById(R.id.btn_close).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getApplicationContext(), "对话框已关闭~", Toast.LENGTH_SHORT).show();
                alert.dismiss();
            }
        });

        btn_show.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                alert.show();
            }
        });
    }
}

AlertDialogDemo.zip 代码下载: https://www.runoob.com/wp-content/uploads/2015/09/AlertDialogDemo.zip

AlertDialogDemo1.zip代码下载: https://www.runoob.com/wp-content/uploads/2015/09/AlertDialogDemo1.zip