从库中选择图像后显示空白屏幕
从库中选择图像后显示空白屏幕
提问于 2021-05-25 02:32:35
我正在尝试将一张图片放入ImageView，但每当我点击Gallery上的图片时，应用程序都会显示一个空白屏幕并关闭。此ImageView在片段中
公共视图容器( inflater.inflate(R.layout.fragment_auction_add，onCreateView，LayoutInflater容器，捆绑容器){ View v= ViewGroup savedInstanceState，false)；
auction_add_imageViewButton = v.findViewById(R.id.auction_add_imageView_button);
auction_add_imageViewButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
imageSelectAction(v);
}
});
dateTimeAction(v);
return v;
}
private void imageSelectAction(View v) {
auction_add_imageViewButton = v.findViewById(R.id.auction_add_imageView_button);
auction_add_image = v.findViewById(R.id.auction_add_imageView);
choosePicture();
}
private void choosePicture() {
Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Select Picture"), SELECT_PICTURE);
}
@Override
public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
if (requestCode == SELECT_PICTURE) {
if (data != null && data.getData() != null) {
Uri selectedImageUri = data.getData();
auction_add_image.setImageURI(selectedImageUri);
}
}
}
}最初的宣言
public class auction_add extends Fragment {
private static final int SELECT_PICTURE = 10;
private static final int PERMISSION_CODE = 11;
ImageButton auction_add_imageViewButton;
//References to all Auction Add Page EditText
EditText auction_add_itemNameTxt;
EditText auction_add_descriptionTxt;
EditText auction_add_initialPriceTxt;
EditText auction_add_startTimeTxt;
EditText auction_add_endTimeTxt;
//Reference to ImageView
private ImageView auction_add_image;
final Calendar myCalendar = Calendar.getInstance();感谢您的帮助！
编辑：
下面是Android Studio的Run选项卡上的错误
W/System: A resource failed to call close.
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.projectcrest, PID: 5618
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=242868079, result=-1, data=Intent { dat=content://com.android.providers.media.documents/document/image:31 flg=0x1 }} to activity {com.example.projectcrest/com.example.projectcrest.pages.LandingPage}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageURI(android.net.Uri)' on a null object reference
at android.app.ActivityThread.deliverResults(ActivityThread.java:5015)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:5056)
at android.app.servertransaction.ActivityResultItem.execute(ActivityResultItem.java:51)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageURI(android.net.Uri)' on a null object reference
at com.example.projectcrest.fragments.auction_add.onActivityResult(auction_add.java:155)
at androidx.fragment.app.FragmentManager$9.onActivityResult(FragmentManager.java:2905)
at androidx.fragment.app.FragmentManager$9.onActivityResult(FragmentManager.java:2885)
at androidx.activity.result.ActivityResultRegistry.doDispatch(ActivityResultRegistry.java:377)
at androidx.activity.result.ActivityResultRegistry.dispatchResult(ActivityResultRegistry.java:336)
at androidx.activity.ComponentActivity.onActivityResult(ComponentActivity.java:624)
at androidx.fragment.app.FragmentActivity.onActivityResult(FragmentActivity.java:164)
at android.app.Activity.dispatchActivityResult(Activity.java:8310)
at android.app.ActivityThread.deliverResults(ActivityThread.java:5008)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:5056)
at android.app.servertransaction.ActivityResultItem.execute(ActivityResultItem.java:51)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
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)
I/Process: Sending signal. PID: 5618 SIG: 9回答 1
Stack Overflow用户
回答已采纳
发布于 2021-05-25 03:22:11
通过查看异常，似乎应用程序在行auction_add_image.setImageURI(selectedImageUri);处的#onActivityResult函数中由于NPE (空指针异常)而崩溃。由于auction_add_image对象具有空值而不是ImageView，因此会导致此预期/崩溃。
仔细查看您的代码后，我认为该问题是由于以下代码造成的：
auction_add_imageViewButton = v.findViewById(R.id.auction_add_imageView_button);
auction_add_imageViewButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
imageSelectAction(v);
}
});注意，在#onClick函数中，您传递的是视图v，您将在该视图上执行#findViewById操作。在这里，传递的视图v引用的是auction_add_imageViewButton，而不是上面捕获的v。
我建议如下修改代码(只需将#onClick函数中的v变量重命名)：
auction_add_imageViewButton = v.findViewById(R.id.auction_add_imageView_button);
auction_add_imageViewButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View buttonView) {
imageSelectAction(v);
}
});这样就可以避免变量名冲突，并解决错误。
另外，如果这不能解决您的问题，请检查#findViewById是否返回ImageView而不是null。如果提供给#findViewById的Id不在屏幕上或视图的子视图中(正在执行#findViewById)，则#findViewById将返回空值。
另外，检查您是否在代码中的任何位置将空值赋给了auction_add_image。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/67677211
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