这是我创建的视图类。
public class WorkoutView extends LinearLayout implements View.OnClickListener {
public Spinner spinnerDifficulty, spinnerTime, spinnerMuscleGroup, spinnerSets, spinnerReps;
public EditText etWorkoutName;
public Button btnRemoveWorkout;
String workoutName, muscleGroup, sets, reps;
LayoutInflater inflater;
Context mContext;
ButtonPressInterface buttonPressCallback;
public WorkoutView(Context context) {
super(context);
Log.e("WORKOUTVIEW", "1");
mContext = context;
}
public WorkoutView(Context context, AttributeSet attrs) {
super(context, attrs);
mContext = context;
Log.e("WORKOUTVIEW", "2");
}
public WorkoutView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mContext = context;
Log.e("WORKOUTVIEW", "3");
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
init();
}
public interface ButtonPressInterface {
void buttonWasPressed();
}
public void init() {
spinnerDifficulty = (Spinner) findViewById(R.id.spinnerDifficulty);
spinnerReps = (Spinner) findViewById(R.id.spinnerReps);
spinnerSets = (Spinner) findViewById(R.id.spinnerSets);
spinnerMuscleGroup = (Spinner) findViewById(R.id.spinnerWorkoutGroup);
spinnerTime = (Spinner) findViewById(R.id.spinnerTime);
etWorkoutName = (EditText) findViewById(R.id.etWorkoutName);
btnRemoveWorkout = (Button) findViewById(R.id.btnRemoveWorkout);
btnRemoveWorkout.setOnClickListener(this);
buttonPressCallback = (ButtonPressInterface) getContext();
}
public String getReps() {
reps = spinnerReps.getSelectedItem().toString();
return reps;
}
public String getWorkoutName() {
workoutName = etWorkoutName.getText().toString().trim();
return workoutName;
}
public String getMuscleGroup() {
muscleGroup = spinnerMuscleGroup.getSelectedItem().toString();
return muscleGroup;
}
public String getSets() {
sets = spinnerSets.getSelectedItem().toString();
return sets;
}
public SingleWorkout getAll() {
//to be designed
return null;
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.btnRemoveWorkout:
buttonPressCallback.buttonWasPressed();
Log.e("DID THIS WORK?", "BUTTON PRESSED");
break;
}
}
}
如何在按btnRemoveWorkout时删除此视图？有没有办法实现接口？正在正确添加此视图，所有其他方法都可以正常工作。
以下是我尝试以编程方式添加视图时收到的错误，在尝试实现回调活动的接口之前，这是可能的。
03-06 23:30:30.352 6986-6986/com.modup.app E/WORKOUTVIEW﹕ 2
03-06 23:30:30.372 6986-6986/com.modup.app E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.modup.app, PID: 6986
java.lang.ClassCastException: com.modup.view.WorkoutView cannot be cast to com.modup.view.WorkoutView$ButtonPressInterface
at com.modup.view.WorkoutView.init(WorkoutView.java:70)
at com.modup.view.WorkoutView.onFinishInflate(WorkoutView.java:52)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:763)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at com.modup.fragment.CreateFragment.onClick(CreateFragment.java:197)
at android.view.View.performClick(View.java:4442)
at android.view.View$PerformClick.run(View.java:18473)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5105)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:792)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:608)
at dalvik.system.NativeStart.main(Native Method)
03-06 23:31:21.972 7620-7620/com.modup.app E/WORKOUTVIEW﹕ 2
03-06 23:31:21.982 7620-7620/com.modup.app E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.modup.app, PID: 7620
java.lang.ClassCastException: com.modup.app.LeftMenusActivity cannot be cast to com.modup.view.WorkoutView$ButtonPressInterface
at com.modup.view.WorkoutView.init(WorkoutView.java:70)
at com.modup.view.WorkoutView.onFinishInflate(WorkoutView.java:52)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:763)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at com.modup.fragment.CreateFragment.onClick(CreateFragment.java:197)
at android.view.View.performClick(View.java:4442)
at android.view.View$PerformClick.run(View.java:18473)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5105)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:792)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:608)
at dalvik.system.NativeStart.main(Native Method)
我期待回应回调的片段内部
@Override
public void buttonWasPressed() {
workoutLayout.removeView(workoutView);
}
更新
我实施了
public void registerButtonPressInterface(ButtonPressInterface listener){
buttonPressCallback = listener;
}
添加视图时不会导致崩溃，但我的按钮仍无效，导致NullPointerException。
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.btnRemoveWorkout:
buttonPressCallback.buttonWasPressed();
Log.e("DID THIS WORK?", "BUTTON PRESSED");
break;
}
}
这就是我试图收听回调的方式
workoutView.registerButtonPressInterface(new WorkoutView.ButtonPressInterface() {
@Override
public void buttonWasPressed() {
Log.e("BUTTON WAS PRESSED", "INTERFACE WORKED!");
}
});
workoutLayout.addView(workoutView);
答案 0 :(得分：1)
根据您的堆栈跟踪，这是导致胃灼热的一行：
buttonPressCallback = (ButtonPressInterface) getContext();
您没有发布相关代码，但我敢打赌您认为您的活动实际上并非如此。实际上，你说你的最后一个代码片段（它是接口实现）来自片段。
以下是我的建议：不要将上下文强制转换为界面，而是创建方法
public void registerButtonPressListener(ButtonPressInterface listener)
并存储对ButtonPressInterface实现的引用。这将使您的视图类更加灵活，因为您的上下文不需要实现ButtonPressInterface才能使用您的视图。现在，编译器将能够告诉您传入的内容实际上是否实现了接口，并且您将更容易找出错误。