1.引言
Dialog是对话框的基类,可以实现以下子类:
AlertDialog,DatePickerDialog,TimPickerDialog。
这些类为你定义了样式和结构,不过你可以使用DialogFragment作为对话框的内容。通过DialogFragment你可以自由控制你的对话框,而不是继承Dialog对象沿用Dialog对象的一些方法。
当用户按返回键或屏幕翻转的时候要注意DialogFragment的生命周期。DialogFragment也允许你把它的UI用在打的UI上。
如果使用Support library记得引用android.support.v4.app.DialogFragment而不是android.app.DialogFragment
.
2.一个最简单的例子
public class FireMissilesDialogFragment extends DialogFragment { @Override public Dialog onCreateDialog(Bundle savedInstanceState) { // Use the Builder class for convenient dialog construction AlertDialog.Builder builder = new AlertDialog.Builder(getActivity()); builder.setMessage(R.string.dialog_fire_missiles) .setPositiveButton(R.string.fire, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { // FIRE ZE MISSILES! } }) .setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { // User cancelled the dialog } }); // Create the AlertDialog object and return it return builder.create(); } }
当你想显示Dialog时,只需调用show()
3.方法回调
在DialogFragment中设置一个interface,通过这个接口可以将事件传递到主activity中
public class NoticeDialogFragment extends DialogFragment { /* The activity that creates an instance of this dialog fragment must * implement this interface in order to receive event callbacks. * Each method passes the DialogFragment in case the host needs to query it. */ public interface NoticeDialogListener { public void onDialogPositiveClick(DialogFragment dialog); public void onDialogNegativeClick(DialogFragment dialog); } // Use this instance of the interface to deliver action events NoticeDialogListener mListener; // Override the Fragment.onAttach() method to instantiate the NoticeDialogListener @Override public void onAttach(Activity activity) { super.onAttach(activity); // Verify that the host activity implements the callback interface try { // Instantiate the NoticeDialogListener so we can send events to the host mListener = (NoticeDialogListener) activity; } catch (ClassCastException e) { // The activity doesn‘t implement the interface, throw exception throw new ClassCastException(activity.toString() + " must implement NoticeDialogListener"); } } ... }
4.DialogFragmnt既可以显示为一个全屏的对话框,亦可以显示为一个嵌入的Fragment
public class CustomDialogFragment extends DialogFragment { /** The system calls this to get the DialogFragment‘s layout, regardless of whether it‘s being displayed as a dialog or an embedded fragment. */ @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout to use as dialog or embedded fragment return inflater.inflate(R.layout.purchase_items, container, false); } /** The system calls this only when creating the layout in a dialog. */ @Override public Dialog onCreateDialog(Bundle savedInstanceState) { // The only reason you might override this method when using onCreateView() is // to modify any dialog characteristics. For example, the dialog includes a // title by default, but your custom layout might not need it. So here you can // remove the dialog title, but you must call the superclass to get the Dialog. Dialog dialog = super.onCreateDialog(savedInstanceState); dialog.requestWindowFeature(Window.FEATURE_NO_TITLE); return dialog; } }
public void showDialog() { FragmentManager fragmentManager = getSupportFragmentManager(); CustomDialogFragment newFragment = new CustomDialogFragment(); if (mIsLargeLayout) { // The device is using a large layout, so show the fragment as a dialog newFragment.show(fragmentManager, "dialog"); } else { // The device is smaller, so show the fragment fullscreen FragmentTransaction transaction = fragmentManager.beginTransaction(); // For a little polish, specify a transition animation transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN); // To make it fullscreen, use the ‘content‘ root view as the container // for the fragment, which is always the root view for the activity transaction.add(android.R.id.content, newFragment) .addToBackStack(null).commit(); } }
其中mIsLargeLayout根据当前设备判断是否使用app的大UI布局。
mIsLargeLayout的取值方法如下:
res/values/bools.xml
<!-- Default boolean values --> <resources> <bool name="large_layout">false</bool> </resources>
res/values-large/bools.xml
<!-- Large screen boolean values --> <resources> <bool name="large_layout">true</bool> </resources>
boolean mIsLargeLayout; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mIsLargeLayout = getResources().getBoolean(R.bool.large_layout); }
5.如果你的应用只是适配了小屏幕的手机,那么:
<activity android:theme="@android:style/Theme.Holo.DialogWhenLarge" >
将你的activity设置为Theme.Holo.DialogWhenLarge会在大屏幕上展示为对话框。
android Dialogs
时间: 2024-10-13 13:34:34