以编程方式将应用程序背景图像(>图库、内存)更改为不覆盖第一个图像的另一个图像,应具有相同的优先级

我对Android完全陌生，但我使用了大量的StackOverflow问题来几乎完成我的应用程序。

简而言之，工作流程是：从图库上传图像，使用特定路径将其保存到内部存储中(这意味着，下一个上传的图像也将保存到完全相同的内部路径位置)，然后将其设置为背景(位于现有背景之上，来自XML：android:background="@drawable/bg_app_img，可以很好地工作)。

问题是，在保存级别和保存图像的墙纸设置方面，尝试这样做效果很好，但应用程序的背景效果不好。使用全窗口比例选项设置图像背景(如果它的ImageView是XML文件中倒数第一个-最高优先级)，它不能被当前上传的图像替换。如果XML中的ImageView order is opposite, from highest scaled to lowest, it would be an image above a larger prior chosen image (see image below). So the problem lies with the order of ImageView：第三个(从顶部开始)是全尺寸的ImageView order is opposite, from highest scaled to lowest, it would be an image above a larger prior chosen image (see image below). So the problem lies with the order of ImageView，它被“卡住”，不允许显示其他图像，而第二个不允许显示第一个图像(因为它会显示在它后面+更小)。XML可能定义了优先级，但在我的例子中是不必要的，还有after setting the background, even deleting the Image from internal storage does nothing to the currently shown last uploaded image pixels with their high priority。

已尝试：

1.删除android:background="@drawable/bg_app_img(a可能是(？)拉伸墙纸的解决方案，没有帮助)。
1.在设置新图像之前，再次设置bg_app_img(编码方式相同)：

Uri uri_bg_temp = Uri.parse("android.resource://" + getPackageName() + "/" + 
R.drawable.bg_app_img);
full_ImageView.setImageURI(uri_bg_temp);
smaller_ImageView.setImageURI(yourUri);

不起作用，因为它使“bg_app_img”成为背景，而不是上面的新图像。

1.更改XML文件中3 ImageView的顺序所做的更改没有解决问题，因为较小的ImageView现在可以高于较大的大小(根据XML文件中的优先级)：

1.删除android:scaleType="fitXY"。不用了。
1.同步清除、重建所有缓存和使缓存无效，也没有帮助。

我不想永久更改XML(或应用程序当前打开的时间？)使用代码，因为用户可能选择半比例图像，然后是全比例图像，然后是半比例图像，如果以任何方式删除半(高度)比例的图像，则不会显示-这是不好的。

应该发生什么：从图库中选择的任何新图像都将出现在drawable/bg_app_img上方的背景中，而不是以前从图库中选择的任何图像。

XML代码：

<?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="@drawable/bg_app_img"
    tools:contetx=".day1">

    <TextView
        android:id="@+id/textView6"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_centerInParent="true"
        android:adjustViewBounds="true"
        android:text="Wallpaper preview, image size:"
        android:textAlignment="center"
        android:textColor="@color/black"
        android:textSize="25sp"
        android:translationZ="90dp"
        android:scaleType="center"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/image_view_smallest"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:adjustViewBounds="true"
        android:scaleType="center"
        app:layout_constraintWidth_percent="1"
        app:layout_constraintWidth_default="percent"
        app:layout_constraintHeight_percent="1"
        app:layout_constraintHeight_default="percent" />

    <ImageView
        android:id="@+id/image_view_smaller"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        android:scaleType="center"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:adjustViewBounds="true"
        app:layout_constraintWidth_percent="1"
        app:layout_constraintWidth_default="percent"
        app:layout_constraintHeight_percent="1"
        app:layout_constraintHeight_default="percent" />

    <ImageView
        android:id="@+id/image_view"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:adjustViewBounds="true"
        app:layout_constraintWidth_percent="1"
        app:layout_constraintWidth_default="percent"
        app:layout_constraintHeight_percent="1"
        android:scaleType="fitXY"
        app:layout_constraintHeight_default="percent" />

    <Button
        android:id="@+id/gallery"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:backgroundTint="@color/white"
        android:text="Full"

        android:textAllCaps="false"
        android:textColor="@color/black"
        android:textSize="22sp"
        app:layout_constraintBottom_toTopOf="@+id/textView6"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.2"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/chose_smaller_img" />

    <Button
        android:id="@+id/chose_smaller_img"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:backgroundTint="@color/white"
        android:text="3/4"
        android:textAllCaps="false"
        android:textColor="@color/black"
        android:textSize="22sp"
        app:layout_constraintBottom_toTopOf="@+id/gallery"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.8"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/chose_smallest_img" />

    <Button
        android:id="@+id/chose_smallest_img"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:backgroundTint="@color/white"
        android:text="half"
        android:textAllCaps="false"
        android:textColor="@color/black"
        android:textSize="22sp"
        app:layout_constraintBottom_toTopOf="@+id/chose_smaller_img"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView6" />

</androidx.constraintlayout.widget.ConstraintLayout>

Java类代码：

package com.my_app;

import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.appcompat.app.AppCompatActivity;
import android.app.WallpaperManager;
import android.content.Context;
import android.content.ContextWrapper;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.Point;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.DisplayMetrics;
import android.view.Display;
import android.widget.Button;
import android.widget.ImageView;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Calendar;

public class day1 extends AppCompatActivity {

    //creating a mutable (changeable) bitmap:
    int w = 1, h = 1;
    Bitmap.Config conf = Bitmap.Config.ARGB_8888; // see other conf types
    Bitmap btm = Bitmap.createBitmap(w, h, conf);

    //Saving to internal memory the image as it is
    private void saveToInternalStorage(Bitmap bitmapImage){
        ContextWrapper cw = new ContextWrapper(getApplicationContext());
        // path to /data/data/your_app/app_data/imageDir
        File directory = cw.getDir("imageDir", Context.MODE_PRIVATE);
        // Create imageDir
        File internal_image_saved_path=new File(directory,"day1.jpg");

        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(internal_image_saved_path);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        // Use the compress method on the BitMap object to write image to the OutputStream
            bitmapImage.compress(Bitmap.CompressFormat.PNG, 100, fos);
    }

    //init:
    Uri uri=null;
    Context context=this;

    //day in week:
    Calendar c = Calendar.getInstance();
    int day_in_week = c.get(Calendar.DAY_OF_WEEK);

    //to scale image to window size (stretch)
    Button full_PickImage;
    ImageView full_ImageView;
    ActivityResultLauncher<String> mGetContent;
    //to scale image to window width and 0.75 height size
    Button smaller_PickImage;
    ImageView smaller_ImageView;
    ActivityResultLauncher<String> smallerGetContent;
    //to scale image to window width and 0.5 height size
    Button smallest_PickImage;
    ImageView smallest_ImageView;
    ActivityResultLauncher<String> smallestGetContent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_day1);

        //full size, 3/4, half:
        full_PickImage = findViewById(R.id.gallery);
        full_ImageView = findViewById(R.id.image_view);
        smaller_PickImage = findViewById(R.id.chose_smaller_img);
        smaller_ImageView = findViewById(R.id.image_view_smaller);
        smallest_PickImage = findViewById(R.id.chose_smallest_img);
        smallest_ImageView = findViewById(R.id.image_view_smallest);

        mGetContent = registerForActivityResult(new ActivityResultContracts.GetContent(),
                result -> {
                    full_ImageView.setImageURI(result);
                    uri = result;
                    if(uri!=null) {
                        //uri to bitmap to store in internal storage:
                        try {
                            Bitmap bitmap = MediaStore.Images.Media.getBitmap(context.getContentResolver() , Uri.parse(uri.toString()));

                            //get window width & height size:
                            int[] win_size = win_size();
                            int win_width  = win_size[0];
                            int win_height = win_size[1];

                            //bitmap scaled to win height & width size
                            Bitmap resized_bitmap = getResizedBitmap(bitmap, win_width, win_height);
                            //internal save:
                            saveToInternalStorage(resized_bitmap);
                            //set in App background:
                            show_background_chosen_img(0);
                            btm = resized_bitmap; //used later to set wallpaper (deleted for stackoverflow)
                        }
                        catch (Exception e) {
                            //handle exception
                        }
                    }
                });

        smallerGetContent = registerForActivityResult(new ActivityResultContracts.GetContent(),
                result -> {
                    smaller_ImageView.setImageURI(result);
                    uri = result;

                    if(uri!=null) {
                        //uri to bitmap to store in internal storage:
                        try {
                            Bitmap bitmap = MediaStore.Images.Media.getBitmap(context.getContentResolver() , Uri.parse(uri.toString()));
                            //get win h&w size:
                            int[] win_size = win_size();
                            int win_width= win_size[0];
                            int win_height=(int)(win_size[1] * 0.75);

                            //bitmap scaled to win height & width size
                            Bitmap resized_bitmap = getResizedBitmap(bitmap, win_width, win_height);
                            saveToInternalStorage(resized_bitmap);
                            //set background:
                            show_background_chosen_img(1);
                            btm = resized_bitmap; //used later
                        }
                        catch (Exception e) { 
                            //handle exception
                        }
                    }
                });

        smallestGetContent = registerForActivityResult(new ActivityResultContracts.GetContent(),
                result -> {
                    smallest_ImageView.setImageURI(result);
                    uri = result;

                    if(uri!=null) {
                        //uri to bitmap to store in internal storage:
                        try {
                            Bitmap bitmap = MediaStore.Images.Media.getBitmap(context.getContentResolver() , Uri.parse(uri.toString()));
                            //get win h&w size:
                            int[] win_size = win_size();
                            int win_width= (int)(win_size[0]);
                            int win_height=(int)(win_size[1] * 0.5);

                            //bitmap scaled to window height & width size (from above...)
                            Bitmap resized_bitmap = getResizedBitmap(bitmap, win_width, win_height);
                            saveToInternalStorage(resized_bitmap);
                            //set background:
                            show_background_chosen_img(2);
                            btm = resized_bitmap; //used later
                        }
                        catch (Exception e) {
                            //handle exception
                        }
                    }
                });

        full_PickImage.setOnClickListener(v -> mGetContent.launch("image/*"));
        smaller_PickImage.setOnClickListener(v -> smallerGetContent.launch("image/*"));
        smallest_PickImage.setOnClickListener(v -> smallestGetContent.launch("image/*"));
    }
    public Bitmap getResizedBitmap(Bitmap bm, int newWidth, int newHeight) {
        int width = bm.getWidth();
        int height = bm.getHeight();
        float scaleWidth = ((float) newWidth) / width;
        float scaleHeight = ((float) newHeight) / height;
        // CREATE A MATRIX FOR THE MANIPULATION
        Matrix matrix = new Matrix();
        // RESIZE THE BIT MAP
        matrix.postScale(scaleWidth, scaleHeight);
        // "RECREATE" THE NEW BITMAP
        Bitmap resizedBitmap = Bitmap.createBitmap(
                bm, 0, 0, width, height, matrix, false);
        bm.recycle();
        return resizedBitmap;
    }
    // get phone window size
    public int[] win_size(){
        Display display = getWindowManager(). getDefaultDisplay();
        Point size = new Point();
        display. getSize(size);
        int win_width = size.x;
        int win_height = size.y;
        return new int[] {win_width, win_height};
    }

    public void show_background_chosen_img(int type){
        //show current loaded image at first enter to class
        ContextWrapper cw = new ContextWrapper(getApplicationContext());
        // path to /data/data/your_app/app_data/imageDir
        File directory = cw.getDir("imageDir", Context.MODE_PRIVATE);
        File f = new File(directory, "day1.jpg");
        if (f.exists()) {
            Uri yourUri = Uri.fromFile(f);
            if (type==0) {
                //Uri uri_bg_temp = Uri.parse("android.resource://" + getPackageName() + "/" + R.drawable.bg_app_img);
                //full_ImageView.setImageURI(uri_bg_temp);
                full_ImageView.setImageURI(yourUri);
            }
            else if (type==1){
                //Uri uri_bg_temp = Uri.parse("android.resource://" + getPackageName() + "/" + R.drawable.bg_app_img);
                //full_ImageView.setImageURI(uri_bg_temp);
                smaller_ImageView.setImageURI(yourUri); }
            else if (type==2) {
                //Uri uri_bg_temp = Uri.parse("android.resource://" + getPackageName() + "/" + R.drawable.bg_app_img);
                //smallest_ImageView.setImageURI(uri_bg_temp);
                smallest_ImageView.setImageURI(yourUri); }
        }
    }
}

如果您觉得Main类及其XML，甚至build.gradle也需要，请让我知道。B.t.w，bg_app_image.png是e1d11d1文件(即使它可能与问题无关)。谢谢!

以编程方式将应用程序背景图像(>图库、内存)更改为不覆盖第一个图像的另一个图像,应具有相同的优先级

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