0、相关资料
https://www.jianshu.com/p/cd3557b1a474
https://www.cnblogs.com/lyysz/p/6344507.html
1、代码实战：下载图片
1.1、依赖
// 依赖RxAndroid 2X 的依赖库
// 增加RxJava 2X 的依赖库
implementation 'io.reactivex.rxjava2:rxandroid:2.0.1'
implementation 'io.reactivex.rxjava2:rxjava:2.1.3'
1.2、清单文件
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.test.enjoy12">
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:usesCleartextTraffic="true"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/Theme.EnjoyClass12"
>
<activity android:name=".DownloadActivity"></activity>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
1.3、activity
public class DownloadActivity extends AppCompatActivity {
// 打印logcat日志的标签
private static final String TAG = "DownloadActivity";
// 网络图片的链接地址
private final static String PATH = "http://bpic.588ku.com/element_origin_min_pic/16/10/29/2ac8e99273bc079e40a8dc079ca11b1f.jpg";
private final static String PATH_RX = "http://bpic.588ku.com/element_origin_min_pic/17/06/13/5c5a1442f0ec72e59829ee10d891f224.jpg%21r650";
// 弹出加载框
private ProgressDialog progressDialog;
// ImageView控件，用来显示结果图像
private ImageView image;
private ImageView ivGlide;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_download);
image = findViewById(R.id.image);
ivGlide = findViewById(R.id.iv_glide);
// Glide.with(this).load(PATH).into(ivGlide);
}
// 零零散散 麻烦 思维
public void downloadImageAction(View view) {
progressDialog = new ProgressDialog(this);
progressDialog.setTitle("下载图片中...");
progressDialog.show();
new Thread(() -> {
try {
URL url = new URL(PATH);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setConnectTimeout(5000);
//设置请求方法
httpURLConnection.setRequestMethod("GET");
int responseCode = httpURLConnection.getResponseCode(); // 才开始 request
if (responseCode == HttpURLConnection.HTTP_OK) {
InputStream inputStream = httpURLConnection.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
Message message = handler.obtainMessage();
message.obj = bitmap;
handler.sendMessage(message);
}
} catch (Exception e) {
e.printStackTrace();
}
}).start();
}
private final Handler handler = new Handler(new Handler.Callback() {
@Override
public boolean handleMessage(@NonNull Message msg) {
Bitmap bitmap = (Bitmap) msg.obj;
image.setImageBitmap(bitmap);
if (progressDialog != null) progressDialog.dismiss();
return false;
}
});
public void rxJavaDownloadImageAction(View view) {
// 起点
Observable.just(PATH) // 内部会分发 PATH Stirng // TODO 第二步
// TODO 第三步
.map(new Function<String, Bitmap>() {
@Override
public Bitmap apply(@NotNull String s) throws Exception {
Log.i(TAG, "apply: ");
URL url = new URL(PATH_RX);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setConnectTimeout(5000);
//设置请求方法
httpURLConnection.setRequestMethod("GET");
int responseCode = httpURLConnection.getResponseCode(); // 才开始 request
if (responseCode == HttpURLConnection.HTTP_OK) {
InputStream inputStream = httpURLConnection.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
return bitmap;
}
return null;
}
})
.subscribeOn(Schedulers.io()) //给上面代码分配异步线程
.observeOn(AndroidSchedulers.mainThread()) //给下面代码分配主线程
// 订阅 起点 和 终点 订阅起来
.subscribe(new Observer<Bitmap>() {
@Override
public void onSubscribe(@NotNull Disposable d) {
Log.i(TAG, "onSubscribe: ");
// 预备 开始 要分发
// TODO 第一步
progressDialog = new ProgressDialog(DownloadActivity.this);
progressDialog.setTitle("download run");
progressDialog.show();
}
// TODO 第四步
// 拿到事件
@Override
public void onNext(@NotNull Bitmap bitmap) {
Log.i(TAG, "onNext: ");
ivGlide.setImageBitmap(bitmap);
}
@Override
public void onError(@NotNull Throwable e) {
}
// TODO 第五步
// 完成事件
@Override
public void onComplete() {
Log.i(TAG, "onComplete: ");
if (progressDialog != null)
progressDialog.dismiss();
}
});
}
}
1.4、布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="downloadImageAction"
android:text="传统方式下载图片功能" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="rxJavaDownloadImageAction"
android:text="RxJava方式下载图片功能" />
<ImageView
android:id="@+id/image"
android:layout_width="match_parent"
android:layout_height="200dp" />
<ImageView
android:id="@+id/iv_glide"
android:layout_width="match_parent"
android:layout_height="200dp" />
</LinearLayout>
2、代码实战：封转线程切换
public class DownloadActivity extends AppCompatActivity {
// 打印logcat日志的标签
private static final String TAG = "DownloadActivity";
// 网络图片的链接地址
private final static String PATH = "http://bpic.588ku.com/element_origin_min_pic/16/10/29/2ac8e99273bc079e40a8dc079ca11b1f.jpg";
private final static String PATH_RX = "http://bpic.588ku.com/element_origin_min_pic/17/06/13/5c5a1442f0ec72e59829ee10d891f224.jpg%21r650";
// 弹出加载框
private ProgressDialog progressDialog;
// ImageView控件，用来显示结果图像
private ImageView image;
private ImageView ivGlide;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_download);
image = findViewById(R.id.image);
ivGlide = findViewById(R.id.iv_glide);
// Glide.with(this).load(PATH).into(ivGlide);
}
// 零零散散 麻烦 思维
public void downloadImageAction(View view) {
progressDialog = new ProgressDialog(this);
progressDialog.setTitle("下载图片中...");
progressDialog.show();
new Thread(() -> {
try {
URL url = new URL(PATH);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setConnectTimeout(5000);
//设置请求方法
httpURLConnection.setRequestMethod("GET");
int responseCode = httpURLConnection.getResponseCode(); // 才开始 request
if (responseCode == HttpURLConnection.HTTP_OK) {
InputStream inputStream = httpURLConnection.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
Message message = handler.obtainMessage();
message.obj = bitmap;
handler.sendMessage(message);
}
} catch (Exception e) {
e.printStackTrace();
}
}).start();
}
private final Handler handler = new Handler(new Handler.Callback() {
@Override
public boolean handleMessage(@NonNull Message msg) {
Bitmap bitmap = (Bitmap) msg.obj;
image.setImageBitmap(bitmap);
if (progressDialog != null) progressDialog.dismiss();
return false;
}
});
/**
* 封装我们的操作
* Upstream 上游
* Downstream 下游
*/
public final static <UD> ObservableTransformer<UD, UD> rxud() {
return new ObservableTransformer<UD, UD>() {
@Override
public ObservableSource<UD> apply(Observable<UD> upstream) {
return upstream.subscribeOn(Schedulers.io()) // 给上面代码分配异步线程
.observeOn(AndroidSchedulers.mainThread()) // 给下面代码分配主线程;
.map(new Function<UD, UD>() {
@Override
public UD apply(UD ud) throws Exception {
Log.d(TAG, "apply: 我监听到你了，居然在执行");
return ud;
}
});
// .....
}
};
}
public void rxJavaDownloadImageAction(View view) {
// 起点
Observable.just(PATH) // 内部会分发 PATH Stirng // TODO 第二步
// TODO 第三步
.map(new Function<String, Bitmap>() {
@Override
public Bitmap apply(@NotNull String s) throws Exception {
Log.i(TAG, "apply: ");
URL url = new URL(PATH_RX);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setConnectTimeout(5000);
//设置请求方法
httpURLConnection.setRequestMethod("GET");
int responseCode = httpURLConnection.getResponseCode(); // 才开始 request
if (responseCode == HttpURLConnection.HTTP_OK) {
InputStream inputStream = httpURLConnection.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
return bitmap;
}
return null;
}
})
// 图片上绘制文字 加水印
.map(new Function<Bitmap, Bitmap>() {
@Override
public Bitmap apply(Bitmap bitmap) throws Exception {
Paint paint = new Paint();
paint.setTextSize(88);
paint.setColor(Color.RED);
return drawTextToBitmap(bitmap, "同学们大家好", paint, 88, 88);
}
})
// 每次都写这个线程切换比较麻烦，可以考虑进行封装
// .subscribeOn(Schedulers.io()) //给上面代码分配异步线程
// .observeOn(AndroidSchedulers.mainThread()) //给下面代码分配主线程
// 替代上面两行代码
.compose(rxud())
// 订阅 起点 和 终点 订阅起来
.subscribe(new Observer<Bitmap>() {
@Override
public void onSubscribe(@NotNull Disposable d) {
Log.i(TAG, "onSubscribe: ");
// 预备 开始 要分发
// TODO 第一步
progressDialog = new ProgressDialog(DownloadActivity.this);
progressDialog.setTitle("download run");
progressDialog.show();
}
// TODO 第四步
// 拿到事件
@Override
public void onNext(@NotNull Bitmap bitmap) {
Log.i(TAG, "onNext: ");
ivGlide.setImageBitmap(bitmap);
}
@Override
public void onError(@NotNull Throwable e) {
}
// TODO 第五步
// 完成事件
@Override
public void onComplete() {
Log.i(TAG, "onComplete: ");
if (progressDialog != null)
progressDialog.dismiss();
}
});
}
// 图片上绘制文字 加水印
private final Bitmap drawTextToBitmap(Bitmap bitmap, String text, Paint paint, int paddingLeft, int paddingTop) {
Bitmap.Config bitmapConfig = bitmap.getConfig();
paint.setDither(true); // 获取跟清晰的图像采样
paint.setFilterBitmap(true);// 过滤一些
if (bitmapConfig == null) {
bitmapConfig = Bitmap.Config.ARGB_8888;
}
bitmap = bitmap.copy(bitmapConfig, true);
Canvas canvas = new Canvas(bitmap);
canvas.drawText(text, paddingLeft, paddingTop, paint);
return bitmap;
}
}
|