Java RatingBar DialogFragment关闭后Android应用程序崩溃
我的应用程序的目的是通过自定义对话框从评级栏中检索出一个5分的值,并将其显示在主活动的文本视图中。当我点击下图中我用红色标出的按钮时,应用程序崩溃并关闭 该应用程序由2个类/活动组成。主活动和自定义对话框活动 这两个文件的代码如下所示: MainActivity.java:Java RatingBar DialogFragment关闭后Android应用程序崩溃,java,android,android-dialogfragment,ratingbar,Java,Android,Android Dialogfragment,Ratingbar,我的应用程序的目的是通过自定义对话框从评级栏中检索出一个5分的值,并将其显示在主活动的文本视图中。当我点击下图中我用红色标出的按钮时,应用程序崩溃并关闭 该应用程序由2个类/活动组成。主活动和自定义对话框活动 这两个文件的代码如下所示: MainActivity.java: package com.example.mealrater; import androidx.appcompat.app.AppCompatActivity; import androidx.fragment.app.
package com.example.mealrater;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity implements MealRaterDialog.SaveRating {
public EditText restaurant, dish;
public TextView ratingDisplay;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
restaurant = findViewById(R.id.etRestaurant);
dish = findViewById(R.id.etDish);
RateMealButton();
}
@Override
public void finishMealRaterDialog(String rating) {
ratingDisplay = findViewById(R.id.tvRatingDisplay);
ratingDisplay.setText(rating);
}
private void RateMealButton() {
Button rate = findViewById(R.id.btnRate);
rate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
FragmentManager fm = getSupportFragmentManager();
MealRaterDialog mealRaterDialog = new MealRaterDialog();
mealRaterDialog.show(fm, "RateMeal");
}
});
}
}
MealRaterDialog.java:
package com.example.mealrater;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.RatingBar;
import androidx.fragment.app.DialogFragment;
public class MealRaterDialog extends DialogFragment {
String rating;
public interface SaveRating {
void finishMealRaterDialog(String rating);
}
public MealRaterDialog() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.meal_rater, container);
getDialog().setTitle("Rate your meal");
Button save = view.findViewById(R.id.btnSaveRating);
save.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
RatingBar ratingBar = view.findViewById(R.id.rbMeal);
rating = String.valueOf(ratingBar.getRating());
SaveItem(String.valueOf(rating));
}
});
return view;
}
private void SaveItem(String rating) {
MealRaterDialog.SaveRating activity = (MealRaterDialog.SaveRating) getActivity();
activity.finishMealRaterDialog(rating);
getDialog().dismiss();
}
}
2021-04-28 16:04:35.240 18144-18144/com.example.mealrater E/libc: Access denied finding property "ro.serialno"
2021-04-28 16:04:42.709 18144-18144/com.example.mealrater E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.mealrater, PID: 18144
java.lang.NullPointerException: Attempt to invoke virtual method 'float android.widget.RatingBar.getRating()' on a null object reference
at com.example.mealrater.MealRaterDialog$1.onClick(MealRaterDialog.java:35)
at android.view.View.performClick(View.java:7448)
at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1119)
at android.view.View.performClickInternal(View.java:7425)
at android.view.View.access$3600(View.java:810)
at android.view.View$PerformClick.run(View.java:28305)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
我是Android工作室的新手,也希望收到关于如何改进这个问题的提示。多谢各位
日志猫错误:
package com.example.mealrater;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.RatingBar;
import androidx.fragment.app.DialogFragment;
public class MealRaterDialog extends DialogFragment {
String rating;
public interface SaveRating {
void finishMealRaterDialog(String rating);
}
public MealRaterDialog() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.meal_rater, container);
getDialog().setTitle("Rate your meal");
Button save = view.findViewById(R.id.btnSaveRating);
save.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
RatingBar ratingBar = view.findViewById(R.id.rbMeal);
rating = String.valueOf(ratingBar.getRating());
SaveItem(String.valueOf(rating));
}
});
return view;
}
private void SaveItem(String rating) {
MealRaterDialog.SaveRating activity = (MealRaterDialog.SaveRating) getActivity();
activity.finishMealRaterDialog(rating);
getDialog().dismiss();
}
}
2021-04-28 16:04:35.240 18144-18144/com.example.mealrater E/libc: Access denied finding property "ro.serialno"
2021-04-28 16:04:42.709 18144-18144/com.example.mealrater E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.mealrater, PID: 18144
java.lang.NullPointerException: Attempt to invoke virtual method 'float android.widget.RatingBar.getRating()' on a null object reference
at com.example.mealrater.MealRaterDialog$1.onClick(MealRaterDialog.java:35)
at android.view.View.performClick(View.java:7448)
at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1119)
at android.view.View.performClickInternal(View.java:7425)
at android.view.View.access$3600(View.java:810)
at android.view.View$PerformClick.run(View.java:28305)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
对此有几种修复方法 首先,您应该在onClick之前定义ratingBar小部件。现在,每次单击按钮时,它都在创建变量。在
按钮save=view.findviewbyd(R.id.btnSaveRating)之后定义它代码>行
其次,当您使用对话框片段时,应该在名为onViewCreated()
的覆盖函数上调用所有单击逻辑。而不是像您现在所做的那样,在OnCreateView()中。让我知道它是否适用于您。有几种修复方法
首先,您应该在onClick之前定义ratingBar小部件。现在,每次单击按钮时,它都在创建变量。在按钮save=view.findviewbyd(R.id.btnSaveRating)之后定义它代码>行
其次,当您使用对话框片段时,应该在名为onViewCreated()
的覆盖函数上调用所有单击逻辑。而不是像您现在所做的那样,在OnCreateView()中。让我知道它是否适用于您。我已尝试重现此错误,并找到了适合我的解决方案。
您必须创建带有视图的分级栏(在侦听器外部)
这应该是MealRaterDialog.java类中的onCreateView
@覆盖
CreateView上的公共视图(布局、充气机、视图组容器、捆绑包保存状态){
最终视图=充气机。充气(R.布局图。用餐者,容器);
getDialog().setTitle(“评估您的膳食”);
按钮保存=view.findviewbyd(R.id.btnSaveRating);
RatingBar RatingBar=view.findViewById(R.id.rbfeed);
save.setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图){
rating=String.valueOf(ratingBar.getRating());
SaveItem(String.valueOf(rating));
}
});
返回视图;
}
希望它能起作用 我试图重现这个错误,我找到了一个适合我的解决方案。
您必须创建带有视图的分级栏(在侦听器外部)
这应该是MealRaterDialog.java类中的onCreateView
@覆盖
CreateView上的公共视图(布局、充气机、视图组容器、捆绑包保存状态){
最终视图=充气机。充气(R.布局图。用餐者,容器);
getDialog().setTitle(“评估您的膳食”);
按钮保存=view.findviewbyd(R.id.btnSaveRating);
RatingBar RatingBar=view.findViewById(R.id.rbfeed);
save.setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图){
rating=String.valueOf(ratingBar.getRating());
SaveItem(String.valueOf(rating));
}
});
返回视图;
}
希望它能起作用 请粘贴例外stacktrace@fillobotto使用此类的方法:最终对话框=新建对话框(MainActivity.this);对话框.setContentView(R.layout.fine_-rater);RatingBar RatingBar=dialog.findViewById(R.id.rbf);dialog.show()@ahmad bajwa将此代码放在哪个方法下?在主类RateMealButton()函数中。请粘贴异常stacktrace@fillobotto使用此类的方法:最终对话框=新建对话框(MainActivity.this);对话框.setContentView(R.layout.fine_-rater);RatingBar RatingBar=dialog.findViewById(R.id.rbf);dialog.show()@ahmad bajwa将此代码放在哪个方法下?在您的主类RateMealButton()函数中。这很有效。我所要做的就是定义你所说的小部件。它仍然适用于onCreateView(),这是有效的。我所要做的就是定义你所说的小部件。它仍然适用于onCreateView()