fragment监听返回键。有时候在activity中点击了物理返回键，不只是返回上一层。所以这时候需要在fragment中处理物理返回键的事件。
首先创建一个接口
public interface FragmentBackListener {
void onbackForward();
}
宿主在宿主activity中：
public class MainActivity extends Activity {
private FragmentBackListener backListener;
private boolean isInterception = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
public FragmentBackListener getBackListener() {
return backListener;
}
public void setBackListener(FragmentBackListener backListener) {
this.backListener = backListener;
}
public boolean isInterception() {
return isInterception;
}
public void setInterception(boolean isInterception) {
this.isInterception = isInterception;
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
if (isInterception()) {
if (backListener != null) {
backListener.onbackForward();
return false;
}
}
}
return super.onKeyDown(keyCode, event);
}
}
在fragment中
public class MFragment extends Fragment implements FragmentBackListener{
@Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
if(activity instanceof MainActivity){
((MainActivity)activity).setBackListener(this);
((MainActivity)activity).setInterception(true);
}
}
@Override
public void onDetach() {
super.onDetach();
if(getActivity() instanceof MainActivity){
((MainActivity)getActivity()).setBackListener(null);
((MainActivity)getActivity()).setInterception(false);
}
}
@Override
public void onbackForward() {
// 处理fragment的返回事件
}
}