javascript - androidx.appcompat.widget.LinearLayoutCompat 无法转换为 android.widget.LinearLayout

Question

我有一个 Android 应用程序。这个应用程序有十个 Activity ，其中第一个 Activity 是运行的启动屏幕，在一两秒后，应用程序关闭并且不会进入第二个 Activity 我得到的错误是:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.myapplication, PID: 4538
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myapplication/com.example.myapplication.IntroPage}: java.lang.ClassCastException: androidx.appcompat.widget.LinearLayoutCompat cannot be cast to android.widget.LinearLayout
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2665)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6119)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
     Caused by: java.lang.ClassCastException: androidx.appcompat.widget.LinearLayoutCompat cannot be cast to android.widget.LinearLayout
        at com.example.myapplication.IntroPage.onCreate(IntroPage.java:45)
        at android.app.Activity.performCreate(Activity.java:6679)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2618)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 
        at android.app.ActivityThread.-wrap12(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:154) 
        at android.app.ActivityThread.main(ActivityThread.java:6119) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 

这是我的 xml 启动屏幕代码:

 <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    tools:context=".SplashScreen"
    android:background="@color/White">



    <androidx.appcompat.widget.AppCompatImageView
        android:id="@+id/img_gif"
        android:layout_width="match_parent"
        android:layout_height="289dp"
        android:layout_marginTop="8dp"
        android:layout_marginBottom="38dp"
        android:src="@drawable/ic_profile"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.296" />


    <androidx.core.widget.ContentLoadingProgressBar
        android:id="@+id/progress"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_marginTop="4dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.005"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <com.github.ybq.android.spinkit.SpinKitView
        android:id="@+id/spin_kit"
        style="@style/SpinKitView.WanderingCubes"
        android:layout_width="60dp"
        android:layout_height="49dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="36dp"
        android:layout_marginRight="8dp"
        app:SpinKit_Color="@color/orange"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/img_gif"
        app:layout_constraintVertical_bias="0.254" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="135dp"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_marginTop="8dp"
        android:layout_marginBottom="2dp"
        android:gravity="center"
        android:text="@string/powerd_by_maede"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/spin_kit"
        app:layout_constraintVertical_bias="0.48"
        android:layout_marginLeft="8dp"
        app:layout_constraintLeft_toLeftOf="parent"
        android:layout_marginRight="8dp"
        app:layout_constraintRight_toRightOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

这是我的 sec Activity xml:

 <?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"
    android:background="#9bfa5e">

    <androidx.viewpager.widget.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="0dp"
        android:layout_height="435dp"
        tools:layout_constraintRight_creator="1"
        tools:layout_constraintBottom_creator="1"
        app:layout_constraintBottom_toTopOf="@+id/layoutDots"
        app:layout_constraintRight_toRightOf="@+id/layoutDots"
        tools:layout_constraintLeft_creator="1"
        android:layout_marginBottom="8dp"
        app:layout_constraintLeft_toRightOf="@+id/layoutDots" />

    <androidx.appcompat.widget.LinearLayoutCompat
        android:id="@+id/layoutDots"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:gravity="center"
        android:orientation="horizontal"
        tools:layout_constraintBottom_creator="1"
        app:layout_constraintBottom_toBottomOf="parent"
        tools:layout_constraintLeft_creator="1"
        app:layout_constraintLeft_toLeftOf="parent" />

    <View
        android:layout_width="0dp"
        android:layout_height="1dp"
        android:alpha=".5"
        android:background="#222"
        tools:layout_constraintTop_creator="1"
        tools:layout_constraintRight_creator="1"
        tools:layout_constraintBottom_creator="1"
        app:layout_constraintBottom_toTopOf="@+id/btn_next"
        android:layout_marginStart="8dp"
        android:layout_marginEnd="8dp"
        app:layout_constraintRight_toRightOf="parent"
        tools:layout_constraintLeft_creator="1"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="@+id/btn_next" />

    <Button
        android:id="@+id/btn_next"
        android:layout_width="88dp"
        android:layout_height="50dp"
        android:background="@drawable/chevron_right"
        android:textColor="#222"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHorizontal_bias="1"
        app:layout_constraintLeft_toRightOf="@+id/btn_skip"
        app:layout_constraintRight_toRightOf="parent"
        tools:layout_constraintBottom_creator="1"
        tools:layout_constraintLeft_creator="1" />

    <Button
        android:id="@+id/btn_skip"
        android:layout_width="88dp"
        android:layout_height="48dp"
        android:layout_marginBottom="1dp"
        android:background="@null"
        android:text="رد کردن"
        android:textColor="#ffffff"
        android:textSize="20sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="@+id/layoutDots"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="1.0"
        tools:layout_constraintBottom_creator="1"
        tools:layout_constraintLeft_creator="1" />

</androidx.constraintlayout.widget.ConstraintLayout>

这就是我的闪屏 Activity :

   package com.example.myapplication;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.os.Handler;
import androidx.appcompat.app.AppCompatActivity;
import android.view.WindowManager;
import android.widget.ProgressBar;
import com.github.ybq.android.spinkit.sprite.Sprite;
import com.github.ybq.android.spinkit.style.DoubleBounce;
import java.util.Calendar;

public class SplashScreen extends AppCompatActivity {

    SharedPreferences sharedP;
    boolean show_intropage=true;
    Calendar taqwim = Calendar.getInstance();
    int today,date_mod;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_splash_screen);


        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
        //----progress---------------
        ProgressBar progressBar = findViewById(R.id.progress);
        Sprite doubleBounce = new DoubleBounce();
        progressBar.setIndeterminateDrawable(doubleBounce);

        today = taqwim.get(Calendar.DAY_OF_YEAR);

        sharedP = getSharedPreferences(Items.SETTINGS, Context.MODE_PRIVATE);
        show_intropage = sharedP.getBoolean(Items.INTROPAGE,true);

        sharedP.edit().putInt(Items.TODAY, today).apply();




        if (show_intropage){

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {

          Intent Myintent = new Intent(SplashScreen.this,IntroPage.class);
                startActivity(Myintent);
                finish();

            }
        },4000);

           date_mod = taqwim.get(Calendar.DAY_OF_YEAR);
           // Toast.makeText(this, day+"", Toast.LENGTH_SHORT).show();
            sharedP.edit().putInt(Items.DATE_MODIFIED, date_mod).apply();


    }else {

            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {

                    Intent Myintent = new Intent(SplashScreen.this,MainActivity.class);
                    startActivity(Myintent);
                    finish();

                }
            },4000);
        }
    }
}

这是我的第二次 Activity :

    package com.example.myapplication;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import androidx.viewpager.widget.PagerAdapter;
import androidx.viewpager.widget.ViewPager;
import androidx.appcompat.app.AppCompatActivity;
import android.text.Html;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.ToxicBakery.viewpager.transforms.RotateUpTransformer;


public class IntroPage extends AppCompatActivity {

    ViewPager MyviewPager;
    Button btnSkip, btnNext;
    private LinearLayout dotsLayout;
    private TextView[] dots;

    SharedPreferences sharedP;

    int [] layout = {R.layout.slide_01,R.layout.slide_02,R.layout.slide_04};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_intro_page);


        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);

        MyviewPager = (ViewPager) findViewById(R.id.viewpager);

        btnSkip = (Button) findViewById(R.id.btn_skip);
        btnNext = (Button) findViewById(R.id.btn_next);
        dotsLayout = (LinearLayout) findViewById(R.id.layoutDots);
        MyviewPager.setAdapter(new ViewP());

        MyviewPager.setPageTransformer(true, new RotateUpTransformer());
        sharedP = getSharedPreferences(Items.SETTINGS, Context.MODE_PRIVATE);

        addBottomDots(0);


        btnNext.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                int Tedad_items = MyviewPager.getCurrentItem()+1;

                if (Tedad_items < layout.length) {

                    MyviewPager.setCurrentItem(MyviewPager.getCurrentItem()+1);

                } else {

                    startActivity(new Intent(IntroPage.this,MainActivity.class));
                    finish();

                }

            }
        });

        btnSkip.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(IntroPage.this,MainActivity.class));
                finish();

            }
        });

        MyviewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            }
            @Override
            public void onPageSelected(int position) {

                addBottomDots(position);

                if (position == layout.length - 1) {
                    // btnNext.setText("Start");
                    btnNext.setBackgroundResource(R.drawable.check);
                    btnSkip.setVisibility(View.GONE);
                } else {
                    //  btnNext.setText("Next");
                    btnNext.setBackgroundResource(R.drawable.chevron_right);
                    btnSkip.setVisibility(View.VISIBLE);
                }
            }
            @Override
            public void onPageScrollStateChanged(int state) {
            }
        });

    }

    public  class ViewP extends PagerAdapter {

        @Override
        public Object instantiateItem(ViewGroup container, int position) {

            View view= LayoutInflater.from(IntroPage.this).inflate(layout[position],container,false);
            container.addView(view);

            return view;
        }

        @Override
        public int getCount() {
            return layout.length;
        }

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == object;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {

            // View view = (View)object;
            container.removeView((View) object);


        }
    }
    private void addBottomDots(int currentPage) {
        dots = new TextView[layout.length];

        int[] colorsActive = getResources().getIntArray(R.array.array_dot_active);
        int[] colorsInactive = getResources().getIntArray(R.array.array_dot_inactive);

        dotsLayout.removeAllViews();
        for (int i = 0; i < dots.length; i++) {
            dots[i] = new TextView(this);
            dots[i].setText(Html.fromHtml("&#8226;"));
            dots[i].setTextSize(35);
            dots[i].setTextColor(colorsInactive[0]);
            dotsLayout.addView(dots[i]);
        }

        if (dots.length > 0)
            dots[currentPage].setTextColor(colorsActive[0]);
    }
}

Answer 1

问题在这里:

dotsLayout = (LinearLayout) findViewById(R.id.layoutDots);

在您的布局中，您使用的是LinearLayoutCompat。
使用:

LinearLayoutCompat dotsLayout;
dotsLayout = findViewById(R.id.layoutDots);