参考：
android 对话框（Dialog）使用：http://blog.csdn.net/u012005313/article/details/58153917
之前总结了基本的关于 dialog 的使用，经过一段时间的学习，对 dialog 的使用又有了一些新的体会。下面加入一些新的操作，同时完善之前的内容。
dialog 可实现自定义界面，比如登录对话框
首先设置登录界面 - dialog_login.xml：用户名和密码输入框，以及清除按钮和登录按钮
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:padding="8dp"> <TableLayout android:id="@+id/dl_table" android:layout_width="match_parent" android:layout_height="wrap_content" android:stretchColumns="1" android:visibility="visible" tools:layout_editor_absoluteX="8dp" tools:layout_editor_absoluteY="8dp"> <TableRow android:layout_width="match_parent" android:layout_height="wrap_content"> <TextView android:layout_width="60dp" android:layout_height="wrap_content" android:gravity="center" android:text="用户" /> <EditText android:id="@+id/et_user" android:layout_width="match_parent" android:layout_height="wrap_content" /> </TableRow> <TableRow android:layout_width="match_parent" android:layout_height="match_parent"> <TextView android:layout_width="60dp" android:layout_height="wrap_content" android:gravity="center" android:text="密码" /> <EditText android:id="@+id/et_password" android:layout_width="match_parent" android:layout_height="wrap_content" android:inputType="textPassword" /> </TableRow> </TableLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <Button android:id="@+id/btn_clear" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_weight="1" android:text="@string/btn_clear" /> <Button android:id="@+id/btn_login" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_weight="1" android:text="@string/btn_login" /> </LinearLayout> </LinearLayout>将该界面加载生成 View 对象：
View view = View.inflate(this, R.layout.dialog_login, null);Note：View.inflate 详细内容
/** * Inflate a view from an XML resource. This convenience method wraps the {@link * LayoutInflater} class, which provides a full range of options for view inflation. * * @param context The Context object for your activity or application. * @param resource The resource ID to inflate * @param root A view group that will be the parent. Used to properly inflate the * layout_* parameters. * @see LayoutInflater */ public static View inflate(Context context, @LayoutRes int resource, ViewGroup root) { LayoutInflater factory = LayoutInflater.from(context); return factory.inflate(resource, root); }生成 dialog 对象，将自定义视图加载进去：
AlertDialog.Builder builder = new AlertDialog.Builder(this) .setView(view);显示该登录对话框：
builder.show();Note：调用 builder.show 等同于先创建 AlertDialog，再进行显示
/** * Creates an {@link AlertDialog} with the arguments supplied to this * builder and immediately displays the dialog. * <p> * Calling this method is functionally identical to: * <pre> * AlertDialog dialog = builder.create(); * dialog.show(); * </pre> */ public AlertDialog show() { final AlertDialog dialog = create(); dialog.show(); return dialog; }这样就完成了登录对话框的创建，如果想要进一步获取用户输入的信息，点击按钮可以进行操作，增加如下代码：
final EditText etUser = (EditText) view.findViewById(R.id.et_user); final EditText etPassword = (EditText) view.findViewById(R.id.et_password); Button btnClear = (Button) view.findViewById(R.id.btn_clear); btnClear.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { etUser.setText(null); etPassword.setText(null); } }); Button btnLogin = (Button) view.findViewById(R.id.btn_login); btnLogin.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String user = etUser.getText().toString(); String password = etPassword.getText().toString(); Log.e(TAG, "onClick: user = " + user + " password = " + password); Toast.makeText(getApplicationContext(), "user = " + user + " password = " + password, Toast.LENGTH_SHORT).show(); } });Note：如果想要符合 MD 规范，可以使用 AlertDialog 自带的按钮，还可以使用自带的标题栏
继续上面的登录界面，现在已经实现了登录对话框，此时并不需要 activity 背景界面，可以设置 activity 主题为 dialog，消去空白的的登录界面。设置方式 - 修改 AndroidManifest.xml 中对应 activity，设置主题为 dialog 样式：
<activity android:name=".custom.CustomActivity" android:theme="@style/Theme.AppCompat.Light.Dialog.Alert"></activity>但是还得解决登录框取消后，仍会出现背景的问题
可以使用 DialogInterface.OnKeyListener 接口：
/** * Interface definition for a callback to be invoked when a key event is * dispatched to this dialog. The callback will be invoked before the key * event is given to the dialog. */ interface OnKeyListener { /** * Called when a key is dispatched to a dialog. This allows listeners to * get a chance to respond before the dialog. * * @param dialog The dialog the key has been dispatched to. * @param keyCode The code for the physical key that was pressed * @param event The KeyEvent object containing full information about * the event. * @return True if the listener has consumed the event, false otherwise. */ public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event); }具体思路：dialog 注册此接口，出现点击操作时，判断是否是返回键。若是，则关闭整个 activity
AlertDialog alertDialog = builder.create(); DialogInterface.OnKeyListener onKeyListener = new DialogInterface.OnKeyListener() { @Override public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_BACK) { finish(); return true; } return false; } }; alertDialog.setOnKeyListener(onKeyListener);同时还要设置点击屏幕对话框外的区域不结束 dialog：
alertDialog.setCancelable(false);完整代码如下：
View view = View.inflate(this, R.layout.dialog_login, null); AlertDialog.Builder builder = new AlertDialog.Builder(this) .setView(view); final EditText etUser = (EditText) view.findViewById(R.id.et_user); final EditText etPassword = (EditText) view.findViewById(R.id.et_password); Button btnClear = (Button) view.findViewById(R.id.btn_clear); btnClear.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { etUser.setText(null); etPassword.setText(null); } }); Button btnLogin = (Button) view.findViewById(R.id.btn_login); btnLogin.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String user = etUser.getText().toString(); String password = etPassword.getText().toString(); Log.e(TAG, "onClick: user = " + user + " password = " + password); Toast.makeText(getApplicationContext(), "user = " + user + " password = " + password, Toast.LENGTH_SHORT).show(); } }); AlertDialog alertDialog = builder.create(); DialogInterface.OnKeyListener onKeyListener = new DialogInterface.OnKeyListener() { @Override public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_BACK) { finish(); return true; } return false; } }; alertDialog.setOnKeyListener(onKeyListener); alertDialog.setCancelable(false); alertDialog.show();参考：
AlertDialog点击按钮后对话框不消失的处理方法
此时，不管是否有输入，点击按钮后对话框自动消失，可通过设置按钮点击事件实现手动决定对话框是否消失。
实现方法：在对话框初始化阶段，设置按钮点击事件为 null；显示对话框后，设置按钮点击事件，即可手动决定是否 dismiss 对话框
修改后代码如下：
View view = View.inflate(this, R.layout.dialog_login, null); final EditText etUser = (EditText) view.findViewById(R.id.et_user); final EditText etPassword = (EditText) view.findViewById(R.id.et_password); AlertDialog.Builder builder = new AlertDialog.Builder(this) .setTitle(getResources().getString(R.string.app_name)) .setView(view) .setPositiveButton(getResources().getString(R.string.btn_login), null) .setNegativeButton(getResources().getString(R.string.btn_clear), null); AlertDialog alertDialog = builder.create(); DialogInterface.OnKeyListener onKeyListener = new DialogInterface.OnKeyListener() { @Override public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_BACK) { finish(); return true; } return false; } }; alertDialog.setOnKeyListener(onKeyListener); alertDialog.setCancelable(false); alertDialog.show(); alertDialog.getButton(Dialog.BUTTON_POSITIVE).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String user = etUser.getText().toString(); String password = etPassword.getText().toString(); Log.e(TAG, "onClick: user = " + user + " password = " + password); Toast.makeText(getApplicationContext(), "user = " + user + " password = " + password, Toast.LENGTH_SHORT).show(); } }); alertDialog.getButton(Dialog.BUTTON_NEGATIVE).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { etUser.setText(null); etPassword.setText(null); } });一个开源的，符合 MD 设计规范的对话框
github：material-dialogs
使用方式和 dialog 类似
android 内置了日期选择对话框和时间选择对话框组件
获取当前年，月，日：
Calendar calendar = Calendar.getInstance(); int year = calendar.get(Calendar.YEAR); int month = calendar.get(Calendar.MONTH); int day = calendar.get(Calendar.DAY_OF_MONTH);创建 DatePickerDialog 并显示：
DatePickerDialog datePickerDialog = new DatePickerDialog(this, this, year, month, day); datePickerDialog.show();另外，需要设置回调接口 DatePickerDialog.OnDateSetListener
完整代码如下：
public class DatePickerActivity extends AppCompatActivity implements DatePickerDialog.OnDateSetListener { private static final String TAG = DatePickerActivity.class.getSimpleName(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_date_picker); Calendar calendar = Calendar.getInstance(); int year = calendar.get(Calendar.YEAR); int month = calendar.get(Calendar.MONTH); int day = calendar.get(Calendar.DAY_OF_MONTH); DatePickerDialog datePickerDialog = new DatePickerDialog(this, this, year, month, day); datePickerDialog.show(); } @Override public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) { Log.e(TAG, "onDateSet: year = " + year + " month = " + month + " day = " + dayOfMonth); } }获取当前时间：
Calendar calendar = Calendar.getInstance(); int hour = calendar.get(Calendar.HOUR_OF_DAY); int minute = calendar.get(Calendar.MINUTE);创建 TimePickerDialog 并显示：
TimePickerDialog timePickerDialog = new TimePickerDialog(this, this, hour, minute, true); timePickerDialog.show();另外，需要设置回调接口 TimePickerDialog.OnDateSetListener
完整代码如下：
public class TimePickerActivity extends AppCompatActivity implements TimePickerDialog.OnTimeSetListener { private static final String TAG = TimePickerDialog.class.getSimpleName(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_time_picker); Calendar calendar = Calendar.getInstance(); int hour = calendar.get(Calendar.HOUR_OF_DAY); int minute = calendar.get(Calendar.MINUTE); TimePickerDialog timePickerDialog = new TimePickerDialog(this, this, hour, minute, true); timePickerDialog.show(); } @Override public void onTimeSet(TimePicker view, int hourOfDay, int minute) { Log.e(TAG, "onTimeSet: h = " + hourOfDay + " m = " + minute); } }android 没有滚轮控件，不过网上已经有了很多的开源滚轮控件，参考了其中两个
有时间详细学习一下
android 推荐使用 DialogFragment 用作对话框的容器，这样可保证能够正确处理生命周期事件，同时有利于复用
首先，扩展 DialogFragment 中的 onCreateDilog 方法，创建 AlertDialog 对象并返回：
public class MyDialogFragment extends DialogFragment { @NonNull @Override public Dialog onCreateDialog(Bundle savedInstanceState) { // return super.onCreateDialog(savedInstanceState); AlertDialog.Builder builder = new AlertDialog.Builder(getActivity()) .setTitle("MyDialogFragment") .setMessage("DialogFragment") .setPositiveButton("OK", null) .setNegativeButton("Cancel", null); return builder.create(); } }其次，在 Activity 中创建 MyDialogFragment 实例，并调用 show 方法即可显示对话框：
MyDialogFragment myDialogFragment = new MyDialogFragment(); myDialogFragment.show(getSupportFragmentManager(), "myDialogFragment");Note：show 方法第二个参数是一个标识符
有时候需要将对话框获取到的数据，比如登录对话框中的用户名，密码，传递回 activity 中进行下一步的操作。 DialogFragment 并没有提供类似的功能，需要自定义相应的接口，进行下一步的操作
首先，在 MyDialogFragment.java 中定义接口 MyDialogListener，包含接口函数 onDialogClick，用于按钮的回调：
public interface MyDialogListener { void onDialogClick(String content, int type); }在 MyDialogFragment.java 中定义该接口，同时在 onAttach 函数中实例化该接口：
private MyDialogListener myDialogListener; @Override public void onAttach(Context context) { super.onAttach(context); try { // Instantiate the NoticeDialogListener so we can send events to the host myDialogListener = (MyDialogListener) context; } catch (ClassCastException e) { // The activity doesn't implement the interface, throw exception throw new ClassCastException(context.toString() + " must implement MyDialogListener"); } }在 onCreateDialog 函数中，创建 AlertDialog 过程中，设置按钮的点击事件，调用接口函数，点击 user 按钮，则返回用户名；点击 password 按钮，则返回密码：
@NonNull @Override public Dialog onCreateDialog(Bundle savedInstanceState) { View view = View.inflate(getContext(), R.layout.dialog_login, null); final EditText etUser = (EditText) view.findViewById(R.id.et_user); final EditText etPassword = (EditText) view.findViewById(R.id.et_password); AlertDialog.Builder builder = new AlertDialog.Builder(getActivity()) .setTitle("MyDialogFragment") .setView(view) .setPositiveButton("user", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { myDialogListener.onDialogClick(etUser.getText().toString(), 1); } }) .setNegativeButton("password", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { myDialogListener.onDialogClick(etPassword.getText().toString(), 2); } }); return builder.create(); }在宿主 activity 中绑定该接口，实现接口函数功能：
public class DialogFragmentActivity extends AppCompatActivity implements MyDialogFragment.MyDialogListener { private TextView textView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_dialog_fragment); textView = (TextView) findViewById(R.id.text); MyDialogFragment myDialogFragment = new MyDialogFragment(); myDialogFragment.show(getSupportFragmentManager(), "myDialogFragment"); } @Override public void onDialogClick(String content, int type) { if (type == 1) { textView.setText("user: " + content); } else { textView.setText("password: " + content); } } }DialogFragment 没有内置函数 setCanceledOnTouchOutside，可以在创建 AlertDialog 时设置该函数：
AlertDialog alertDialog = builder.create(); alertDialog.setCanceledOnTouchOutside(false);不应该直接调用 AlertDialog.setCancelable 方法，而是使用 DialogFragment 内置函数 setCancelable
myDialogFragment.setCancelable(false);Note：可通过调用 isCancelable 获取 DialogFragment 状态
调用 DialogFragment 内置函数 dismiss 即可：
@Override protected void onDestroy() { super.onDestroy(); myDialogFragment.dismiss(); }android 系统自带了一个进度条对话框 - ProgressDialog。 在进行信息查询，数据上传时，可使用该对话框提示用户等待。
ProgressDialog
Note：在程序中可能需要多次进行数据操作，可以创建一个 ProgressDialog 实例并保留下来
创建对话框实例后，需要调用 show 方法显示该对话框
如果需要多次使用 ProgressDialog，只需要创建一个 ProgressDialog 实例，在不需要使用时调用 hide 函数进行隐藏：
/** * Hide the dialog, but do not dismiss it. */ public void hide() { if (mDecor != null) { mDecor.setVisibility(View.GONE); } }最后在结束时，可以调用 dismiss 函数将对话框清除：
/** * Dismiss this dialog, removing it from the screen. This method can be * invoked safely from any thread. Note that you should not override this * method to do cleanup when the dialog is dismissed, instead implement * that in {@link #onStop}. */ @Override public void dismiss() { if (Looper.myLooper() == mHandler.getLooper()) { dismissDialog(); } else { mHandler.post(mDismissAction); } }OSChina：https://git.oschina.net/zjZSTU/dialogdemo.git
