为什么使用DialogFragment
- 可以在屏幕旋转或按下返回键可以更好的处理其生命周期
- 在平板中可以将其嵌入在UI中,类似传统的fragment的使用
怎么使用DialogFragment
- 重写onCreateView()方法
```
public class MyDialogFragment extends DialogFragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState){
View view = inflater.inflate(R.layout.fragment_dialog, container);
return view;
}
}
```
- 重写onCreateDialog()方法
public class MyDialogFragment extends DialogFragment {
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
AlertDialog.Builder builder = new AlertDialog.Builder(getContext(),R.style.theme);
builder.setTitle("对话框");
View view = inflater.inflate(R.layout.fragment_dialog, container);
builder.setView(view);
builder.setPositiveButton("确定", null);
builder.setNegativeButton("取消", null);
return builder.create();
}
}
- 调用方式
MyDialogFragment fragment= new MyDialogFragment ();
fragment.show(getFragmentManager(), "MyDialogment");
- 可根据屏幕尺寸决定将fragment显示为对话框还是全屏
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();
}
}
事件传递
- 宿主为activity
官方指南中是通过fragment的onAttach()方法,将activity强转为回调listener.
```
public class NoticeDialogFragment extends DialogFragment {
public interface NoticeDialogListener {
public void onDialogPositiveClick(DialogFragment dialog);
public void onDialogNegativeClick(DialogFragment dialog);
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mListener = (NoticeDialogListener) activity;
} catch (ClassCastException e) {
// The activity doesn't implement the interface, throw exception
throw new ClassCastException(activity.toString()
+ " must implement NoticeDialogListener");
}
}
}
```
> 宿主通过实现listener,来完成回调
```
public class MainActivity extends FragmentActivity
implements NoticeDialogFragment.NoticeDialogListener{
public void showNoticeDialog() {
DialogFragment dialog = new NoticeDialogFragment();
dialog.show(getSupportFragmentManager(), "NoticeDialogFragment");
}
@Override
public void onDialogPositiveClick(DialogFragment dialog) {
}
@Override
public void onDialogNegativeClick(DialogFragment dialog) {
}
}
```
- 宿主为fragment
> 通过fragment的onActivityResult方法来进行回调,需要设置targetFragment
宿主设置
```
public class HostFragment extends Fragment{
//开启dialog
public void showDialog{
MyDialogFragment fragment= new MyDialogFragment();
fragment.setTargetFragment(context, REQUEST_CODE);
fragment.show(getFragmentManager(), "MyDialogment");
}
//宿主回调
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
switch (requestCode) {
case REQUEST_CODE:
//do something
break;
}
}
}
}
```
调用回调
```
getTargetFragment().onActivityResult(getTargetRequestCode(), Activity.RESULT_OK, data);
```
- 混合情况.作为一个common的dialog
> 参考[Android DialogFragment 在页面销毁下的使用方式 \- 简书](http://www.jianshu.com/p/5ba9f36a4a90)
疑难杂症
- 调用show方法的时候会出现IllegalStateException
具体原因可见 记一个DialogFragment.show()的Bug - 简书
```
//重写show方法加入try/catch
public class BaseDialogFragment extends AppCompatDialogFragment {
@Override
public void show(FragmentManager manager, String tag) {
try {
super.show(manager, tag);
} catch (IllegalStateException e) {
e.printStackTrace();
}
}
}
```