如何从Android Java中的网页获取信息（android获取网页内容）

25-03-03 9

在本文中，您将会了解到关于如何从AndroidJava中的网页获取信息的新资讯，同时我们还将为您解释android获取网页内容的相关在本文中，我们将带你探索如何从AndroidJava中的网页获取信息

在本文中，您将会了解到关于如何从Android Java中的网页获取信息的新资讯，同时我们还将为您解释android获取网页内容的相关在本文中，我们将带你探索如何从Android Java中的网页获取信息的奥秘，分析android获取网页内容的特点，并给出一些关于android – 从网页获取文本到字符串、android – 如何从图像中获取信息？、android – 如何通过条形码获取信息？、android中从java中获取图像时android中的java.lang.OutOfMemoryError的实用技巧。

本文目录一览：

如何从Android Java中的网页获取信息（android获取网页内容）
android – 从网页获取文本到字符串
android – 如何从图像中获取信息？
android – 如何通过条形码获取信息？
android中从java中获取图像时android中的java.lang.OutOfMemoryError

如何从Android Java中的网页获取信息（android获取网页内容）

香港专业教育学院一直试图从网页上获取信息成字符串到我的Android应用程序.我一直在使用这种方法.

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;


public class DownloadPage {

    private static int arraySize;

    public static int getArraySize() throws IOException {

        URL url = new URL("http://woah.x10host.com/randomfact2.PHP");

        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        InputStream in = new BufferedInputStream(urlConnection.getInputStream());
        BufferedReader br = new BufferedReader(new InputStreamReader(in, "UTF-8"));

        String size = br.readLine();

        arraySize = Integer.parseInt(size);

        return arraySize;
    }



}

我什至在我的AndroidManifest.xml文件中包含了权限

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

但是,我一直收到错误,我的应用程序无法启动.每当我调用方法或类时,它就会崩溃.

解决方法:

您似乎正在获取android.os.networkonmainthreadException.
请尝试使用AsyncTask来获取该整数.

public class DownloadPage {

    private static int arraySize;

    public void getArraySize() throws IOException {

        new RetrieveInt().execute();
    }

    private class RetrieveInt extends AsyncTask<String, Void, Integer> {


        @Override
        protected Integer doInBackground(String ... params) {
            try {
                URL url = new URL("http://woah.x10host.com/randomfact2.PHP");

                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                InputStream in = new BufferedInputStream(urlConnection.getInputStream());
                BufferedReader br = new BufferedReader(new InputStreamReader(in, "UTF-8"));

                String size = br.readLine();

                arraySize = Integer.parseInt(size);


            } catch (Exception e) {
                //do something
            }
            return arraySize; // gets 18
        }


        protected void onPostExecute(Integer i) {

            // Todo: do something with the number
// You would get value of i == 18 here. This methods gets called after your doInBackground() with output.
            System.out.println(i); 
        }
    }


}

android – 从网页获取文本到字符串

我是Android新手,我希望将整个文本从网页变为字符串.我发现了很多像这样的问题,但正如我所说,我是Android新手,我不知道如何在我的应用程序中使用它们.我收到了错误.只有一种方法我设法使它工作,它使用WebView和JavaScript,它很慢,因为地狱.有人可以告诉我一些其他的方法来做到这一点或如何加快WebView,因为我根本不使用它来查看内容.
顺便说一下,我添加了以下代码来加速WebView

webView.getSettings().setJavaScriptEnabled(true); 
    webView.getSettings().setBlockNetworkImage(true);
    webView.getSettings().setJavaScriptCanopenWindowsAutomatically(false);
    webView.getSettings().setPluginsEnabled(false);
    webView.getSettings().setSupportMultipleWindows(false);
    webView.getSettings().setSupportZoom(false);
    webView.getSettings().setSavePassword(false);
    webView.setVerticalScrollBarEnabled(false);
    webView.setHorizontalScrollBarEnabled(false);
    webView.getSettings().setAppCacheEnabled(false);
    webView.getSettings().setCacheMode(WebSettings.LOAD_NO_CACHE);

如果您知道其他比使用WebView更好更快的解决方案,请告诉我主要活动的完整源代码或解释我应该写的地方,这样我就不会出错.

解决方法:

用这个：

public class ReadWebpageAsyncTask extends Activity {
    private TextView textView;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        textView = (TextView) findViewById(R.id.TextView01);
    }

    private class DownloadWebPageTask extends AsyncTask<String, Void, String> {
        @Override
        protected String doInBackground(String... urls) {
            String response = "";
            for (String url : urls) {
                DefaultHttpClient client = new DefaultHttpClient();
                HttpGet httpGet = new HttpGet(url);
                try {
                    HttpResponse execute = client.execute(httpGet);
                    InputStream content = execute.getEntity().getContent();

                    BufferedReader buffer = new BufferedReader(
                            new InputStreamReader(content));
                    String s = "";
                    while ((s = buffer.readLine()) != null) {
                        response += s;
                    }

                } catch (Exception e) {
                    e.printstacktrace();
                }
            }
            return response;
        }

        @Override
        protected void onPostExecute(String result) {
            textView.setText(Html.fromHtml(result));
        }
    }

    public void readWebpage(View view) {
        DownloadWebPageTask task = new DownloadWebPageTask();
        task.execute(new String[] { "http://www.google.com" });

    }
}

main.xml中

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <Button android:layout_height="wrap_content" android:layout_width="match_parent" android:id="@+id/readWebpage" android:onClick="readWebpage" android:text="Load Webpage"></Button>
    <TextView android:id="@+id/TextView01" android:layout_width="match_parent" android:layout_height="match_parent" android:text="Example Text"></TextView>
</LinearLayout>

android – 如何从图像中获取信息？

我尝试将图像细节添加到我的应用程序中,例如拍摄日期,相机型号,宽度,高度,描述….任何人都可以帮助我如何做到这一点.
谢谢.

解决方法:

使用ExifInterface可以获取捕获图像的属性,如果您的相机配置为写入它们.有关详细信息,请参阅link.http://developer.android.com/reference/android/media/ExifInterface.html

android – 如何通过条形码获取信息？

我是一个新的 Android开发人员,我尝试创建一个使用条形码的应用程序.我试试ZXing,很容易.但现在我需要通过条形码获得有关产品的信息.我怎样才能做到这一点？

解决方法

您需要使用某种Web服务来查找与UPC / EAN代码关联的产品信息,例如使用 AsyncTask.快速Google搜索出现在 Internet UPC Database.

以下是他们提供的数据的样本记录：http://www.upcdatabase.com/item/0081697521221

请仔细阅读他们的ToS：http://www.upcdatabase.com/docs/terms.asp

android中从java中获取图像时android中的java.lang.OutOfMemoryError

我正在使用代码从图库中选择一张图片

 public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.gallery);

        Intent i = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

        startActivityForResult(i, SELECT_PICTURE);
    }


    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == SELECT_PICTURE && resultCode == RESULT_OK && null != data) {
            Uri selectedImage = data.getData();
            String[] filePathColumn = { MediaStore.Images.Media.DATA };

            Cursor cursor = getContentResolver().query(selectedImage, filePathColumn, null, null, null);
            cursor.movetoFirst();

            int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
            picturePath = cursor.getString(columnIndex);
            cursor.close();

            Log.v("picturePath", "picturePath: " + picturePath);
            Bitmap bitmap = BitmapFactory.decodeFile(picturePath);

            Intent intentUpload = new Intent(galleryActivity.this, UploadActivity.class);
            // intentUpload.putExtra("BitmapImage", bitmap);
            MyApplicationGlobal.bitmap = bitmap;
            startActivity(intentUpload);
            finish();
        }
    }


public String getPath(Uri uri) {
        String[] projection = { MediaStore.Images.Media.DATA };
        Cursor cursor = managedQuery(uri, projection, null, null, null);
        int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.movetoFirst();
        return cursor.getString(column_index);
    }

但是我收到了错误

 FATAL EXCEPTION: main
 java.lang.OutOfMemoryError
at android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:493)
at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:299)
at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:324)
at com.markphoto_activities.galleryActivity.onActivityResult(galleryActivity.java:59)
at android.app.Activity.dispatchActivityResult(Activity.java:4541)
at android.app.ActivityThread.deliverResults(ActivityThread.java:2740)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:2787)
at android.app.ActivityThread.access$2000(ActivityThread.java:122)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1032)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:132)
at android.app.ActivityThread.main(ActivityThread.java:4025)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
at dalvik.system.NativeStart.main(Native Method)

Log-cat是

: E/dalvikvm-heap(2487): Out of memory on a 17915920-byte allocation.
"main" prio=5 tid=1 RUNNABLE
| group="main" sCount=0 dsCount=0 obj=0x400d5638 self=0x126c8
| sysTid=2487 nice=0 sched=0/0 cgrp=default handle=-1342909336
| schedstat=( 2650512000 283442000 1204 ) utm=226 stm=39 core=1
at android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:493)
at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:299)
at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:324)
at com.markphoto_activities.galleryActivity.onActivityResult(galleryActivity.java:59)
at android.app.Activity.dispatchActivityResult(Activity.java:4541)
at android.app.ActivityThread.deliverResults(ActivityThread.java:2740)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:2787)
at android.app.ActivityThread.access$2000(ActivityThread.java:122)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1032)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:132)
at android.app.ActivityThread.main(ActivityThread.java:4025)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
at dalvik.system.NativeStart.main(Native Method)
: D/skia(2487): libjpeg error 105 <  Ss=%d, Se=%d, Ah=%d, Al=%d> from allocPixelRef [3456   2592]
  : D/skia(2487): --- decoder->decode returned false
  : D/AndroidRuntime(2487): Shutting down VM

解决方法:

尝试这个：

@Override
    protected void onActivityResult(int requestCode, int resultCode,
            Intent imageReturnedIntent) {
        super.onActivityResult(requestCode, resultCode, imageReturnedIntent);

        switch (requestCode) {
        case SELECT_PHOTO:
            if (resultCode == RESULT_OK) {
                Uri selectedImage = imageReturnedIntent.getData();
                try {
                    picImageView.setimageBitmap(decodeUri(selectedImage));
                } catch (FileNotFoundException e) {
                    e.printstacktrace();
                }
            }
        }
    }

然后声明以下函数：

private Bitmap decodeUri(Uri selectedImage) throws FileNotFoundException {
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(
                getContentResolver().openInputStream(selectedImage), null, o);

        final int required_SIZE = 100;

        int width_tmp = o.outWidth, height_tmp = o.outHeight;
        int scale = 1;
        while (true) {
            if (width_tmp / 2 < required_SIZE || height_tmp / 2 < required_SIZE) {
                break;
            }
            width_tmp /= 2;
            height_tmp /= 2;
            scale *= 2;
        }

        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        return BitmapFactory.decodeStream(
                getContentResolver().openInputStream(selectedImage), null, o2);
    }

谢谢.

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