如何从Android中的HTML生成位图？
WebView可以用于此，还是有更好的方法（比如可能直接使用WebView渲染引擎）？怎么样？
我想实现以下方法......
public Bitmap toBitmap(Context context, String html, Rect rect);
...其中html是要呈现的html，而rect是所需位图的框架。
答案 0 :(得分：15)
使用WebView从HTML字符串生成位图的同步方法，可以在AsyncTask中使用：
public Bitmap getBitmap(final WebView w, int containerWidth, int containerHeight, final String baseURL, final String content) {
final CountDownLatch signal = new CountDownLatch(1);
final Bitmap b = Bitmap.createBitmap(containerWidth, containerHeight, Bitmap.Config.ARGB_8888);
final AtomicBoolean ready = new AtomicBoolean(false);
w.post(new Runnable() {
@Override
public void run() {
w.setWebViewClient(new WebViewClient() {
@Override
public void onPageFinished(WebView view, String url) {
ready.set(true);
}
});
w.setPictureListener(new PictureListener() {
@Override
public void onNewPicture(WebView view, Picture picture) {
if (ready.get()) {
final Canvas c = new Canvas(b);
view.draw(c);
w.setPictureListener(null);
signal.countDown();
}
}
});
w.layout(0, 0, rect.width(), rect.height());
w.loadDataWithBaseURL(baseURL, content, "text/html", "UTF-8", null);
}});
try {
signal.await();
} catch (InterruptedException e) {
e.printStackTrace();
}
return b;
}
它有一些限制，但它是一个开始。
答案 1 :(得分：6)
您可以使用draw方法让它在您选择的位图中绘制。我做了一个例子，不要忘记你的清单的互联网和外部存储权利：
public class MainActivity extends Activity {
private WebView mWebView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mWebView = new WebView(this);
setContentView(mWebView);
mWebView.loadUrl("http://tea.ch");
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode != KeyEvent.KEYCODE_BACK) return super.onKeyDown(keyCode, event);
Bitmap bm = Bitmap.createBitmap(200, 300, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bm);
mWebView.draw(c);
OutputStream stream = null;
try {
stream = new FileOutputStream(Environment.getExternalStorageDirectory() +"/teach.png");
bm.compress(CompressFormat.PNG, 80, stream);
if (stream != null) stream.close();
} catch (IOException e) {
} finally {
bm.recycle();
}
return super.onKeyDown(keyCode, event);
}
}
答案 2 :(得分：0)
为什么不使用WebView方法：capturePicture（）返回一个Picture并且自API级别1起可用？
它返回整个文档的图片。
然后，您可以使用矩形裁剪结果并从那里保存位图。
答案 3 :(得分：0)
这个例子展示了如何捕获webView内容的最后一张图片（它等到webview完成渲染图片），这是一个使用Android将HTML转换为PNG的例子
活动代码
public class HtmlViewer extends Activity {
private String HTML;
private Context ctx;
private Picture pic = null;
private int i=0; suppose this is the last pic
private int oldi = 0;
private Timer myTimer; // timer for waiting until last picture loaded
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_html_viewer);
Intent intent = getIntent();
HTML = intent.getStringExtra("HTML");
ctx = this;
WebView wv = (WebView)findViewById(R.id.webView1);
wv.setPictureListener(new PictureListener(){
public void onNewPicture(WebView view, Picture picture) {
Log.w("picture", "loading.." + String.valueOf(view.getProgress()));
pic = picture;
i++;
}
});
wv.loadData(HTML, "text/html; charset=utf-8", null);
wv.setWebViewClient(new WebViewClient()
{
public void onPageFinished(WebView wv, String url)
{
Picture p = wv.capturePicture();
myTimer = new Timer();
myTimer.schedule(new TimerTask() {
@Override
public void run() {
if (i > oldi)
oldi = i;
else
if (i != 0)
{
Log.w("picture", "finished");
cancel();
Picture picture = pic;
Log.w("picture", "onNewPicture- Height"+ picture.getHeight());
Log.w("picture", "onNewPicture- Width"+ picture.getWidth());
File sdCard = Environment.getExternalStorageDirectory();
if (picture != null)
{
Log.w("picture", " P OK");
Bitmap image = Bitmap.createBitmap(picture.getWidth(),picture.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(image);
picture.draw(canvas);
Log.w("picture", "C OK");
if (image != null) {
Log.w("picture", "I OK");
ByteArrayOutputStream mByteArrayOS = new ByteArrayOutputStream();
image.compress(Bitmap.CompressFormat.PNG, 90, mByteArrayOS);
try {
File file = new File(sdCard, "AccountView.PNG");
FileOutputStream fos = new FileOutputStream(file);
fos.write(mByteArrayOS.toByteArray());
fos.flush();
fos.close();
Log.w("picture", "F OK " + String.valueOf(mByteArrayOS.size()) + " ? " + String.valueOf(file.length()));
Intent sharingIntent = new Intent(Intent.ACTION_SEND);
Uri screenshotUri = Uri.fromFile(file);
sharingIntent.setType("image/png");
sharingIntent.putExtra(Intent.EXTRA_STREAM, screenshotUri);
startActivity(Intent.createChooser(sharingIntent, getResources().getString(R.string.ACCOUNT_VIEW_TITLE)));
((Activity)ctx).finish();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
}, 0, 1000);
Log.w("picture", "done");
loadcompleted = true;
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_html_viewer, menu);
return true;
}
}
<强>布局
<LinearLayout 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"
android:orientation="vertical"
tools:context=".HtmlViewer" >
<WebView
android:id="@+id/webView1"
android:layout_width="match_parent"
android:layout_height="match_parent" />
答案 4 :(得分：0)