<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.example.myapplication">
    <!-- 互联网 -->
    <uses-permission android:name="android.permission.INTERNET" />
    <!-- 存储卡 -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.MyApplication"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="5dp">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:orientation="horizontal">
        <CheckBox
            android:id="@+id/ck_seize"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="left|center"
            android:text="是否启用占位图"
            android:textColor="#000000"
            android:textSize="17sp" />
        <CheckBox
            android:id="@+id/ck_error"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="left|center"
            android:text="是否启用出错图"
            android:textColor="#000000"
            android:textSize="17sp" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:orientation="horizontal">
        <CheckBox
            android:id="@+id/ck_original"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="left|center"
            android:text="是否加载原图片"
            android:textColor="#000000"
            android:textSize="17sp" />
        <CheckBox
            android:id="@+id/ck_transition"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="left|center"
            android:text="是否呈现渐变动画"
            android:textColor="#000000"
            android:textSize="17sp" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="缓存策略："
            android:textColor="@color/black"
            android:textSize="17sp" />
        <Spinner
            android:id="@+id/sp_cache_strategy"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:spinnerMode="dialog" />
    </LinearLayout>
    <ImageView
        android:id="@+id/iv_network"
        android:layout_width="match_parent"
        android:layout_height="250dp" />
    <Button
        android:id="@+id/btn_download"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="下载网络图片"
        android:textColor="#000000"
        android:textSize="17sp"
        android:visibility="gone"/>
</LinearLayout>

import android.graphics.drawable.Drawable; import android.net.Uri; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.CheckBox; import android.widget.ImageView; import android.widget.Spinner; import com.bumptech.glide.Glide; import com.bumptech.glide.RequestBuilder; import com.bumptech.glide.load.DataSource; import com.bumptech.glide.load.engine.DiskCacheStrategy; import com.bumptech.glide.load.engine.GlideException; import com.bumptech.glide.load.resource.drawable.DrawableTransitionOptions; import com.bumptech.glide.request.RequestListener; import com.bumptech.glide.request.RequestOptions; import com.bumptech.glide.request.target.Target; import androidx.appcompat.app.AppCompatActivity; import java.io.File; public class MainActivity extends AppCompatActivity private static final String TAG = "GlideCacheActivity" ; private ImageView iv_network; private String mImageUrl = "https://img0.baidu.com/it/u=1305074959,4101321827&fm=253&fmt=auto&app=120&f=JPEG?w=1280&h=800" ; private CheckBox ck_seize; // 声明一个复选框对象。是否启用占位图 private CheckBox ck_error; // 声明一个复选框对象。是否启用出错图 private CheckBox ck_original; // 声明一个复选框对象。是否加载原图片 private CheckBox ck_transition; // 声明一个复选框对象。是否呈现渐变动画 private int mCacheStrategy; // 缓存策略的类型 @Override protected void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.activity_main); iv_network = findViewById(R.id.iv_network); ck_seize = findViewById(R.id.ck_seize); ck_error = findViewById(R.id.ck_error); ck_original = findViewById(R.id.ck_original); ck_transition = findViewById(R.id.ck_transition); ck_seize.setOnCheckedChangeListener((buttonView, isChecked) -> showNetworkImage()); ck_error.setOnCheckedChangeListener((buttonView, isChecked) -> showNetworkImage()); ck_original.setOnCheckedChangeListener((buttonView, isChecked) -> showNetworkImage()); ck_transition.setOnCheckedChangeListener((buttonView, isChecked) -> showNetworkImage()); initStrategySpinner(); // 初始化缓存策略的下拉框 findViewById(R.id.btn_download).setOnClickListener(v -> downloadImage(mImageUrl)); // 初始化缓存策略的下拉框 private void initStrategySpinner() { ArrayAdapter <String> modeAdapter = new ArrayAdapter<String>( this , R.layout.item_select, strategyArray); Spinner sp_cache_strategy = findViewById(R.id.sp_cache_strategy); sp_cache_strategy.setPrompt( "请选择缓存策略" ); sp_cache_strategy.setAdapter(modeAdapter); sp_cache_strategy.setSelection( 0 ); sp_cache_strategy.setOnItemSelectedListener( new StrategySelectedListener()); private String[] strategyArray = {"自动选择缓存策略", "不缓存图片", "只缓存原始图片", "只缓存压缩后的图片", "同时缓存原图和压缩图片" }; class StrategySelectedListener implements AdapterView.OnItemSelectedListener { public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) { mCacheStrategy = arg2; showNetworkImage(); // 加载并显示网络图片 public void onNothingSelected(AdapterView<?> arg0) { // 加载并显示网络图片 private void showNetworkImage() { // 构建一个加载网络图片的建造器 RequestBuilder<Drawable> builder = Glide.with( this ).load(mImageUrl); RequestOptions options = new RequestOptions(); // 创建Glide的请求选项 // options.disallowHardwareConfig(); // 关闭硬件加速，防止过大尺寸的图片加载报错 options.skipMemoryCache( true ); // 是否跳过内存缓存（但不影响硬盘缓存） options.override(300, 200); // 设置图片的宽高 if (ck_seize.isChecked()) { // 勾选了占位图 options.placeholder(R.drawable.load_default); // 设置加载开始的占位图 if (ck_error.isChecked()) { // 勾选了出错图 options.error(R.drawable.load_error); // 设置发生错误的提示图 if (ck_original.isChecked()) { // 勾选了原始图 options.override(Target.SIZE_ORIGINAL); // 展示原始图片 if (ck_transition.isChecked()) { // 勾选了渐变动画 builder.transition(DrawableTransitionOptions.withCrossFade(3000)); // 设置时长3秒的渐变动画 if (mCacheStrategy == 0) { // 自动选择缓存策略 options.diskCacheStrategy(DiskCacheStrategy.AUTOMATIC); // 设置指定的缓存策略 } else if (mCacheStrategy == 1) { // 不缓存图片 options.diskCacheStrategy(DiskCacheStrategy.NONE); // 设置指定的缓存策略 } else if (mCacheStrategy == 2) { // 只缓存原始图片 options.diskCacheStrategy(DiskCacheStrategy.DATA); // 设置指定的缓存策略 } else if (mCacheStrategy == 3) { // 只缓存压缩后的图片 options.diskCacheStrategy(DiskCacheStrategy.RESOURCE); // 设置指定的缓存策略 } else if (mCacheStrategy == 4) { // 同时缓存原始图片和压缩图片 options.diskCacheStrategy(DiskCacheStrategy.ALL); // 设置指定的缓存策略 // 在图像视图上展示网络图片。apply方法表示启用指定的请求选项 builder.apply(options).into(iv_network); // 先下载图片，再显示图片 private void downloadImage(String url) { Glide.with( this ).downloadOnly().load(url).listener( new RequestListener<File> () { @Override public boolean onLoadFailed(GlideException e, Object model, Target<File> target, boolean isFirstResource) { return false ; @Override public boolean onResourceReady(File resource, Object model, Target<File> target, DataSource dataSource, boolean isFirstResource) { Log.d(TAG, "local image path = "+ resource.getAbsolutePath()); iv_network.setImageURI(Uri.parse(resource.getAbsolutePath())); return false ; }).preload();