1. 图片网址url转化为bitmap

1.1. 方法一 通过 HttpURLConnection 请求

  要使用一个线程去访问，因为是网络请求，这是一个一步请求，不能直接返回获取，要不然永远为null，在这里得到BitMap之后记得使用Hanlder或者EventBus传回主线程，不过现在加载图片都是用框架了，很少有转化为Bitmap的需求

    /*** 通过 网络图片 url 获取图片 Bitmap* @param photoUrl 网络图片 url*/private void requestWebPhotoBitmap(String photoUrl) {new Thread(() -> {HttpURLConnection connection = null;try {URL bitmapUrl = new URL(photoUrl);connection = (HttpURLConnection) bitmapUrl.openConnection();connection.setRequestMethod("GET");connection.setConnectTimeout(5000);connection.setReadTimeout(5000);// 判断是否请求成功if (connection.getResponseCode() == 200) {Message hintMessage = new Message();hintMessage.what = HANDLER_START_DOWNLOAD;hintHandler.sendMessage(hintMessage);InputStream inputStream = connection.getInputStream();imgBitmap = BitmapFactory.decodeStream(inputStream);Message message = showHandler.obtainMessage();showHandler.sendMessage(message);} else {Message hintMessage = new Message();hintMessage.what = HANDLER_NET_ERROR;hintHandler.sendMessage(hintMessage);}} catch (IOException e) {e.printStackTrace();} finally {if (connection != null) connection.disconnect();}}).start();}/*** 设置提示*/private final Handler hintHandler = new Handler(Looper.getMainLooper()){@Overridepublic void handleMessage(Message msg) {if(msg.what == HANDLER_START_DOWNLOAD)Toast.makeText(MainActivity.this, "获取图片中，请稍等", Toast.LENGTH_SHORT).show();else if(msg.what == HANDLER_NET_ERROR)Toast.makeText(MainActivity.this, "网络错误，请重试", Toast.LENGTH_SHORT).show();}};/*** 展示图片*/@SuppressLint("HandlerLeak")private final Handler showHandler = new Handler(Looper.getMainLooper()) {@Overridepublic void handleMessage(Message msg) {super.handleMessage(msg);ivPhoto.setImageBitmap(imgBitmap); //填充控件}};

1.2. 方法二 通过 Glide

1.2.1. java

    /*** 获取 网络图片 Bitmap* @param imgUrl 网络图片url*/private void requestWebPhotoBitmap(String imgUrl) {Toast.makeText(MainActivity.this, "获取图片中，请稍等", Toast.LENGTH_SHORT).show();Glide.with(MainActivity.this).asBitmap().load(imgUrl).into(new CustomTarget<Bitmap>() {@SuppressLint("ClickableViewAccessibility")@Overridepublic void onResourceReady(@NonNull Bitmap resource, @Nullable Transition<? super Bitmap> transition) {imgBitmap = resource;ivPhoto.setImageBitmap(imgBitmap)}@Overridepublic void onLoadCleared(@Nullable Drawable placeholder) {}});}

1.2.2. kotlin

   Glide.with(this).asBitmap().load(paramBean.userImg).into(object : CustomTarget<Bitmap?>() {override fun onResourceReady(resource: Bitmap, transition: Transition<in Bitmap?>?) {val bitmap = resource}override fun onLoadCleared(placeholder: Drawable?) {}})

1.3. 调用

    private Bitmap imgBitmap = null;private ImageView ivPhoto;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);ivPhoto = (ImageView) findViewById(R.id.photo);String imgUrl = "https://w.wallhaven.cc/full/l3/wallhaven-l3xk6q.jpg";requestWebPhotoBitmap(imgUrl);}