我正在尝试使用通过 recyclerview 实现的应用程序抽屉创建一个 andorid 启动器 - 基本上我只想拥有设备上所有已安装应用程序的列表。
目前，当我运行活动时它崩溃了，我不太确定为什么。错误字符串指向我的 AppDrawer.java 中的 第 23 行，但我不确定有什么问题
这是持有 recyclerview 的 Activity，AppDrawer.java：
public class AppDrawer extends AppCompatActivity {
RecyclerView recyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.app_drawer);
recyclerView = findViewById(R.id.appsList);
AppAdapter adapter = new AppAdapter(this);
adapter.onCreateViewHolder(recyclerView, 0); // LINE 23
}
}
app_drawer.xml：
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".AppDrawer">
<androidx.recyclerview.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/appsList"/> //RECYCLERVIEW ID
</androidx.constraintlayout.widget.ConstraintLayout>
这是AppAdapter.java：
public class AppAdapter extends RecyclerView.Adapter<AppAdapter.ViewHolder> {
private List<AppObject> appsList;
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView textView;
public ImageView img;
//This is the subclass ViewHolder which simply
//'holds the views' for us to show on each row
public ViewHolder(View itemView) {
super(itemView);
//Finds the views from our row.xml
textView = (TextView) itemView.findViewById(R.id.text);
img = (ImageView) itemView.findViewById(R.id.image);
itemView.setOnClickListener(this);
}
@Override
public void onClick (View v) {
int pos = getAdapterPosition();
Context context = v.getContext();
Intent launchIntent = context.getPackageManager().getLaunchIntentForPackage(appsList.get(pos).getName());
context.startActivity(launchIntent);
Toast.makeText(v.getContext(), appsList.get(pos).getName(), Toast.LENGTH_LONG).show();
}
}
public AppAdapter(Context c) {
//This is where we build our list of app details, using the app
//object we created to store the label, package name and icon
PackageManager pm = c.getPackageManager();
appsList = new ArrayList<AppObject>();
Intent i = new Intent(Intent.ACTION_MAIN, null);
i.addCategory(Intent.CATEGORY_LAUNCHER);
List<ResolveInfo> allApps = pm.queryIntentActivities(i, 0);
for(ResolveInfo ri:allApps) {
AppObject app = new AppObject(ri.loadLabel(pm).toString(), ri.activityInfo.packageName, ri.activityInfo.loadIcon(pm), false);
// app.getName() = ri.loadLabel(pm);
// app.getPackageName() = ri.activityInfo.packageName;
// app.getImage() = ri.activityInfo.loadIcon(pm);
appsList.add(app);
}
}
@Override
public void onBindViewHolder(AppAdapter.ViewHolder viewHolder, int i) {
//Here we use the information in the list we created to define the views
String appLabel = appsList.get(i).getName();
String appPackage = appsList.get(i).getPackageName();
Drawable appIcon = appsList.get(i).getImage();
TextView textView = viewHolder.textView;
textView.setText(appLabel);
ImageView imageView = viewHolder.img;
imageView.setImageDrawable(appIcon);
}
@Override
public int getItemCount() {
//This method needs to be overridden so that Androids knows how many items
//will be making it into the list
return appsList.size();
}
@Override
public AppAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
//This is what adds the code we've written in here to our target view
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View view = inflater.inflate(R.layout.app_drawer_item, parent, false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
}
AppObject.java：
public class AppObject {
private String name,
packageName;
private Drawable image;
private Boolean isAppInDrawer;
public AppObject(String packageName, String name, Drawable image, Boolean isAppInDrawer) {
this.name = name;
this.image = image;
this.packageName = packageName;
this.isAppInDrawer = isAppInDrawer;
}
public String getPackageName() {
return packageName;
}
public String getName() {
return name;
}
public Drawable getImage() {
return image;
}
public Boolean getIsAppInDrawer() {return isAppInDrawer;}
public void setPackageName(String packageName) {
this.packageName = packageName;
}
public void setName(String name) {
this.name = name;
}
public void setImage(Drawable image) {
this.image = image;
}
public void setIsAppInDrawer(Boolean appInDrawer) {
this.isAppInDrawer = appInDrawer;
}
}
和app_drawer_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:orientation="horizontal"
android:layout_margin="5sp">
<ImageView
android:layout_width="40sp"
android:layout_height="40sp"
android:id="@+id/applicationIconImageView"
android:src="@mipmap/ic_launcher"/>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_marginHorizontal="5sp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/applicationNameTextView"
android:text="Application name"
android:textSize="15sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/usageTimeTextView"
android:text="3h20m"
android:textSize="10sp"
android:layout_marginTop="2sp"/>
</LinearLayout>
</LinearLayout>
这是我尝试运行代码时收到的错误消息：
06/29 18:23:14: Launching 'app' on Physical Device.
App restart successful without requiring a re-install.
$ adb shell am start -n "com.example.launcherapplication/com.example.launcherapplication.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Connected to process 7600 on device 'oneplus-oneplus_a6003-9bb351ae'.
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
I/cherapplicatio: Late-enabling -Xcheck:jni
E/cherapplicatio: Unknown bits set in runtime_flags: 0x8000
I/Perf: Connecting to perf service.
I/cherapplicatio: [GL_OOM] ClampGrowthLimit 268435456
V/Font: Change font:2
Default family:android.graphics.Typeface@73f3fc13
E/Perf: Fail to get file list com.example.launcherapplication
getFolderSize() : Exception_1 = java.lang.NullPointerException: Attempt to get length of null array
E/Perf: Fail to get file list com.example.launcherapplication
getFolderSize() : Exception_1 = java.lang.NullPointerException: Attempt to get length of null array
V/FlingOptimizerScroller: FlingOptimizerOverScroller Init
W/cherapplicatio: Accessing hidden method Landroid/view/View;->computeFitSystemWindows(Landroid/graphics/Rect;Landroid/graphics/Rect;)Z (greylist, reflection, allowed)
Accessing hidden method Landroid/view/ViewGroup;->makeOptionalFitsSystemWindows()V (greylist, reflection, allowed)
W/cherapplicatio: Accessing hidden method Landroid/graphics/FontFamily;-><init>()V (greylist, reflection, allowed)
Accessing hidden method Landroid/graphics/FontFamily;->addFontFromAssetManager(Landroid/content/res/AssetManager;Ljava/lang/String;IZIII[Landroid/graphics/fonts/FontVariationAxis;)Z (greylist, reflection, allowed)
W/cherapplicatio: Accessing hidden method Landroid/graphics/FontFamily;->addFontFromBuffer(Ljava/nio/ByteBuffer;I[Landroid/graphics/fonts/FontVariationAxis;II)Z (greylist, reflection, allowed)
Accessing hidden method Landroid/graphics/FontFamily;->freeze()Z (greylist, reflection, allowed)
Accessing hidden method Landroid/graphics/FontFamily;->abortCreation()V (greylist, reflection, allowed)
Accessing hidden method Landroid/graphics/Typeface;->createFromFamiliesWithDefault([Landroid/graphics/FontFamily;Ljava/lang/String;II)Landroid/graphics/Typeface; (greylist, reflection, allowed)
V/ViewRootImpl: The specified message queue synchronization barrier token has not been posted or has already been removed
D/DecorView: onWindowFocusChangedFromViewRoot hasFocus: true, DecorView@f194ef9[MainActivity]
I/AdrenoGLES: QUALCOMM build : 35556ba, I9ca166462c
Build Date : 08/07/19
OpenGL ES Shader Compiler Version: EV031.27.02.00
Local Branch :
Remote Branch :
Remote Branch :
Reconstruct Branch :
Build Config : S P 8.0.8 AArch64
I/AdrenoGLES: PFP: 0x016ee187, ME: 0x00000000
W/Gralloc3: mapper 3.x is not supported
D/: Successfully load libgui-plugin.so, this=0x7f2fa37050
W/Choreographer: Already have a pending vsync event. There should only be one at a time.
D/OnePlusJankManager: Chor uploadMDM JANK_TYPE_ONCE mViewTitle = com.example.launcherapplication/com.example.launcherapplication.MainActivity--- jank level = 1
W/ActivityThread: handleWindowVisibility: no activity for token android.os.BinderProxy@365f0dd
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
I/chatty: uid=10302(com.example.launcherapplication) identical 48 lines
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
I/chatty: uid=10302(com.example.launcherapplication) identical 12 lines
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
I/chatty: uid=10302(com.example.launcherapplication) identical 6 lines
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
W/cherapplicatio: resources.arsc in APK '/data/app/com.oneplus.gallery-u0eFcDkuFtHGko86_UqHPA==/base.apk' is compressed.
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
I/chatty: uid=10302(com.example.launcherapplication) identical 24 lines
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
W/cherapplicatio: resources.arsc in APK '/data/app/com.facebook.orca-omRvfq_ufIlgi54ffkzO9g==/base.apk' is compressed.
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
I/chatty: uid=10302(com.example.launcherapplication) identical 23 lines
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
I/chatty: uid=10302(com.example.launcherapplication) identical 33 lines
E/OpApplicationPackageManagerInjector: Application package com.oneplus.iconpack.square not found
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.launcherapplication, PID: 7600
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.launcherapplication/com.example.launcherapplication.AppDrawer}: android.view.InflateException: Binary XML file line #2 in com.example.launcherapplication:layout/app_drawer_item: RecyclerView has no LayoutManager androidx.recyclerview.widget.RecyclerView{ce38366 VFED..... ......I. 0,0-0,0 #7f0a0045 app:id/appsList}, adapter:null, layout:null, context:com.example.launcherapplication.AppDrawer@dd5bdd9
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3374)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3513)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2109)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7682)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
Caused by: android.view.InflateException: Binary XML file line #2 in com.example.launcherapplication:layout/app_drawer_item: RecyclerView has no LayoutManager androidx.recyclerview.widget.RecyclerView{ce38366 VFED..... ......I. 0,0-0,0 #7f0a0045 app:id/appsList}, adapter:null, layout:null, context:com.example.launcherapplication.AppDrawer@dd5bdd9
Caused by: java.lang.IllegalStateException: RecyclerView has no LayoutManager androidx.recyclerview.widget.RecyclerView{ce38366 VFED..... ......I. 0,0-0,0 #7f0a0045 app:id/appsList}, adapter:null, layout:null, context:com.example.launcherapplication.AppDrawer@dd5bdd9
at androidx.recyclerview.widget.RecyclerView.generateLayoutParams(RecyclerView.java:4514)
at android.view.LayoutInflater.inflate(LayoutInflater.java:669)
at android.view.LayoutInflater.inflate(LayoutInflater.java:534)
at com.example.launcherapplication.AppAdapter.onCreateViewHolder(AppAdapter.java:104)
at com.example.launcherapplication.AppDrawer.onCreate(AppDrawer.java:23)
at android.app.Activity.performCreate(Activity.java:7815)
at android.app.Activity.performCreate(Activity.java:7804)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1318)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3349)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3513)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2109)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7682)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
I/Process: Sending signal. PID: 7600 SIG: 9
答案 0 :(得分：0)
您的错误显示为 RecyclerView has no LayoutManager androidx.recyclerview.widget.RecyclerView，因此可以尝试将其添加为：
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(mLayoutManager);
答案 1 :(得分：0)
您必须为 RecyclerView 设置一个 LayoutManager。例如，对于垂直滚动列表，您应该像这样使用 LinearLayoutManager。
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.app_drawer);
recyclerView = findViewById(R.id.appsList);
// add this
recyclerView.setLayoutManager(new LinearLayoutManager(this));
AppAdapter adapter = new AppAdapter(this);
// replace this line by this two. (you should not call adapter method directly).
// adapter.onCreateViewHolder(recyclerView, 0); // LINE 23
recyclerView.setAdapter(adapter);
// notify the adapter that the data has changed
recyclerView.notifyDataSetChanged();
}