仿真器未显示为预览中的显示

Question

我不知道问题出在哪里，但我正在尝试制作一个故事应用程序，而且似乎无法使模拟器以与预览相同的方式显示。我使用的是Nexus6模拟器，并在“预览”上预览了所有示例，以查看它们是否有所不同，但它们都显示良好（在预览中）。没有错误显示，没有问题的渐变构建，没有问题的仿真器启动；也许我怀疑custom_view布局可能存在“问题”；我不确定。

logcat错误（我还不知道如何读取logcat，但是这些显示为红色）

2020-10-07 01:48:22.901 1663-1680/system_process E/BluetoothAdapter: Bluetooth binder is null
2020-10-07 01:48:22.902 1663-1680/system_process E/BatteryStatsService: no controller energy info supplied
2020-10-07 01:48:22.909 1663-1680/system_process E/KernelCpuSpeedReader: Failed to read cpu-freq: /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state (No such file or directory)
2020-10-07 01:48:22.909 1663-1680/system_process E/KernelUidCpuTimeReader: Failed to read uid_cputime: /proc/uid_cputime/show_uid_stat (No such file or directory)
2020-10-07 01:48:22.910 1663-1680/system_process E/BatteryStatsService: modem info is invalid: ModemActivityInfo{ mTimestamp=0 mSleepTimeMs=0 mIdleTimeMs=0 mTxTimeMs[]=[0, 0, 0, 0, 0] mRxTimeMs=0 mEnergyUsed=0}
2020-10-07 01:58:00.135 1663-1677/system_process I/ProcessStatsService: Prepared write state in 4ms

custom_view布局

 <?xml version="1.0" encoding="utf-8"?>
    <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:id="@+id/linearLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#0278ae"
    android:padding="5dp">


    <androidx.cardview.widget.CardView
        android:id="@+id/cardView"
        android:layout_width="wrap_content"
        android:layout_height="141dp"
        app:cardCornerRadius="6dp"
        app:cardElevation="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="397dp"
            android:layout_height="match_parent"
            android:padding="5dp">

            <ImageView
                android:id="@+id/imageView"
                android:layout_width="155dp"
                android:layout_height="143dp"
                android:background="@drawable/quran"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toStartOf="@+id/storyContent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintVertical_bias="0.0" />

            <TextView
                android:id="@+id/storyTitle"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="sample text"
                android:textColor="#51adcf"
                android:textSize="20sp"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintHorizontal_bias="0.745"
                app:layout_constraintStart_toStartOf="@+id/imageView"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintVertical_bias="0.219" />

            <TextView
                android:id="@+id/storyContent"
                android:layout_width="242dp"
                android:layout_height="25dp"
                android:text="ٍSample story content (dEscription)"
                android:textColor="#51adcf"
                android:textSize="16sp"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toEndOf="@+id/imageView"
                app:layout_constraintTop_toBottomOf="@+id/storyTitle" />
        </androidx.constraintlayout.widget.ConstraintLayout>
    </androidx.cardview.widget.CardView>
</androidx.constraintlayout.widget.ConstraintLayout>

适配器类（调用custom_view的地方）

package com.example.taletale;


import androidx.annotation.NonNull;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.recyclerview.widget.RecyclerView;

public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
    private LayoutInflater inflater;
    private String[] sTitles;
    private String[] sContent;
    Adapter(Context context, String[] titles, String[] contents){
        this.inflater=LayoutInflater.from(context);
        this.sTitles=titles;
        this.sContent=contents;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View view = inflater.inflate(R.layout.custom_view, viewGroup,false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder viewholder, int i) {
        String title = sTitles[i];
        String content = sContent[i];
        viewholder.storyTitle.setText(title);
        viewholder.storyContent.setText(content);
    }

    @Override
    public int getItemCount() {
        return sTitles.length;
    }

    public class ViewHolder extends RecyclerView.ViewHolder{
       TextView storyTitle,storyContent;
        public ViewHolder(@NonNull View itemView){
            super(itemView);
            storyTitle=itemView.findViewById(R.id.storyTitle);
            storyContent = itemView.findViewById(R.id.storyContent);
        }
    }
}

main_activity类

package com.example.taletale;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;

public class MainActivity extends AppCompatActivity {
    RecyclerView recyclerView;
    Adapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //get the list of stories, titles and contents, in the stories-array
        String[] titles = getResources().getStringArray(R.array.stories_titles);
        String[] contents = getResources().getStringArray(R.array.stories__content);
        recyclerView = findViewById(R.id.StoriesListView);
        adapter = new Adapter(this,titles,contents); //sets adapter to take two string arrays
        recyclerView.setAdapter(adapter);
    }
}

main_activity布局

<?xml version="1.0" encoding="utf-8"?>
<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=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/StoriesListView"
        android:layout_width="409dp"
        android:layout_height="729dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="1.0" />
</androidx.constraintlayout.widget.ConstraintLayout>

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