使用Picasso将url转换为imageView

时间：2017-05-15 12:33:32

标签： java android json xml picasso

我正在使用Picasso将url转换为imageView但收到错误。这是我想稍后从json获取url的demo url但是demo url甚至无法正常工作。请检查是否有人可以解决。

WordActivity.java 

package com.example.anandparmeetsingh.books;

import android.app.LoaderManager;
import android.content.Context;
import android.content.Loader;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import com.squareup.picasso.Picasso;

import java.util.ArrayList;
import java.util.List;

public class WordActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<List<Word>> {
    private static final String LOG_TAG = WordActivity.class.getName();
    /**
     * URL for word data from the USGS dataset
     */
    private static String USGS_REQUEST_URL =
            "https://www.googleapis.com/books/v1/volumes?q=harrypotter";
    /**
     * Adapter for the list of earthquakes
     */
    public WordAdapter mAdapter;
    ListView wordListView;
    ArrayList<Word> words;
    private TextView mEmptyStateTextView;
    private String mQuery = "";
    private ImageView imageView;

    @Override
    protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        setContentView(R.layout.activity_word);
        // Get a reference to the LoaderManager, in order to interact with loaders.
        wordListView = (ListView) findViewById(R.id.list);
        words = new ArrayList<>();
        mAdapter = new WordAdapter(WordActivity.this, words);


        // Create a new adapter that takes an empty list of earthquakes as input


        // Set the adapter on the {@link ListView}
        // so the list can be populated in the user interface

        wordListView.setAdapter(mAdapter);

        // Set an item click listener on the ListView, which sends an intent to a web browser
        // to open a website with more information about the selected word.


        // Set the adapter on the {@link ListView}
        // so the list can be populated in the user interface

        // Start the AsyncTask to fetch the word data
        mEmptyStateTextView = (TextView) findViewById(R.id.empty_view);
        wordListView.setEmptyView(mEmptyStateTextView);
        ConnectivityManager connMgr = (ConnectivityManager)
                getSystemService(Context.CONNECTIVITY_SERVICE);
        imageView = (ImageView) findViewById(R.id.imageView);

        Picasso.with(this)
                .load("http://books.google.com/books/content?id=JGQBcu5O_ZcC&printsec=frontcover&img=1&zoom=1&edge=curl&source=gbs_api")
                .resize(200,200)
                .into(imageView);
        // Get details on the currently active default data network
        final NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
        if (USGS_REQUEST_URL == null || networkInfo == null) {
            wordListView.setEmptyView(mEmptyStateTextView);
            mEmptyStateTextView = (TextView) findViewById(R.id.empty_view);
        }
        // If there is a network connection, fetch data

        final EditText mEditText = (EditText) findViewById(R.id.search_go_btn);
        Button btn = (Button) findViewById(R.id.button);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (USGS_REQUEST_URL == null || networkInfo == null) {
                    wordListView.setEmptyView(mEmptyStateTextView);
                    mEmptyStateTextView = (TextView) findViewById(R.id.empty_view);
                }
                USGS_REQUEST_URL = "https://www.googleapis.com/books/v1/volumes?q=";
                //mAdapter.notifyDataSetChanged();
                // Get the text from the EditText and update the mQuery value.
                mQuery = mEditText.getText().toString().replaceAll(" ", "+");
                // If it's empty don't proceed.
                if (mQuery.isEmpty()) {
                    Toast.makeText(WordActivity.this, "Nothing to search", Toast.LENGTH_SHORT).show();
                }
                // Update the mRequestUrl value with the new mQuery.
                USGS_REQUEST_URL = USGS_REQUEST_URL + mQuery + "&maxResults=15";
                Log.i("onQueryTextSubmit", "mRequestUrl value is: " + USGS_REQUEST_URL);
                // Restart the loader.
                LoaderManager loaderManager = getLoaderManager();
                loaderManager.restartLoader(1, null, WordActivity.this);
                Log.i("onClick", "loader restarted");
                View progressBar = findViewById(R.id.progress_bar);
                progressBar.setVisibility(View.VISIBLE);
                // Try to make the progress bar appear again (not working)
                //View progressBar = findViewById(R.id.progress_bar);
                //progressBar.setVisibility(View.VISIBLE);
                // Update mRequestUrl back to its original value.
                USGS_REQUEST_URL = "https://www.googleapis.com/books/v1/volumes?q=";
                // This is what makes the ListView update with new info.

            }
        });
        if (networkInfo != null && networkInfo.isConnected()) {
            // Get a reference to the LoaderManager, in order to interact with loaders.
            LoaderManager loaderManager = getLoaderManager();

            // Initialize the loader. Pass in the int ID constant defined above and pass in null for
            // the bundle. Pass in this activity for the LoaderCallbacks parameter (which is valid
            // because this activity implements the LoaderCallbacks interface).
            loaderManager.initLoader(1, null, this);
        } else {
            // Otherwise, display error
            // First, hide loading indicator so error message will be visible
            View loadingIndicator = findViewById(R.id.progress_bar);
            loadingIndicator.setVisibility(View.GONE);

            //Update empty state with no connection error message
            wordListView.setEmptyView(mEmptyStateTextView);
            mEmptyStateTextView = (TextView) findViewById(R.id.empty_view);
            mEmptyStateTextView.setText("No Connection");
        }


    }

    public Loader<List<Word>> onCreateLoader(int i, Bundle bundle) {
        return new WordLoader(this, USGS_REQUEST_URL);
    }

    /**
     * {@link } to perform the network request on a background thread, and then
     * update the UI with the list of earthquakes in the response.
     * <p>
     * AsyncTask has three generic parameters: the input type, a type used for progress updates, and
     * an output type. Our task will take a String URL, and return an EarthquakeAdapter. We won't do
     * progress updates, so the second generic is just Void.
     * <p>
     * We'll only override two of the methods of AsyncTask: doInBackground() and onPostExecute().
     * The doInBackground() method runs on a background thread, so it can run long-running code
     * (like network activity), without interfering with the responsiveness of the app.
     * Then onPostExecute() is passed the result of doInBackground() method, but runs on the
     * UI thread, so it can use the produced data to update the UI.
     */

    @Override
    public void onLoadFinished(Loader<List<Word>> loader, List<Word> earthquakes) {
        // Clear the adapter of previous word data
        View loadingIndicator = findViewById(R.id.progress_bar);
        loadingIndicator.setVisibility(View.GONE);
        words.clear();
        // If there is a valid list of {@link Earthquake}s, then add them to the adapter's
        // data set. This will trigger the ListView to update.

        if (earthquakes != null && !earthquakes.isEmpty()) {
            words.addAll(earthquakes);
        } else {
            wordListView.setEmptyView(mEmptyStateTextView);
            mEmptyStateTextView.setText("No Connection");
        }
        mAdapter.notifyDataSetChanged();

      /*  words.addAll(earthquakes);
        mAdapter.notifyDataSetChanged();*/
    }

    @Override
    public void onLoaderReset(Loader<List<Word>> loader) {
        // Loader reset, so we can clear out our existing data.
        words.clear();
    }


}

错误消息

05-15 17:46:35.512 21319-21319/com.example.anandparmeetsingh.booklisting E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.anandparmeetsingh.booklisting, PID: 21319
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.anandparmeetsingh.booklisting/com.example.anandparmeetsingh.books.WordActivity}: java.lang.IllegalArgumentException: Target must not be null.
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2659)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2724)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1473)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6123)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)
Caused by: java.lang.IllegalArgumentException: Target must not be null.
at com.squareup.picasso.RequestCreator.into(RequestCreator.java:553)
at com.squareup.picasso.RequestCreator.into(RequestCreator.java:536)
at com.example.anandparmeetsingh.books.WordActivity.onCreate(WordActivity.java:75)
at android.app.Activity.performCreate(Activity.java:6672)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1140)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2612)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2724) 
at android.app.ActivityThread.-wrap12(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1473) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:154) 
at android.app.ActivityThread.main(ActivityThread.java:6123) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)

activity_word.xml 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="com.example.anandparmeetsingh.books.Book">


    <TextView
        android:id="@+id/magnitude"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:fontFamily="sans-serif-medium"
        android:padding="12dp"
        android:paddingTop="5dp"
        android:text="Title"
        android:textAlignment="center"
        android:textColor="#616161"
        android:textSize="32sp" />
    <ImageView
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_below="@id/magnitude"
        android:layout_centerInParent="true"
        android:id="@+id/imageView"/>

    <TextView
        android:id="@+id/location_offset"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/imageView"
        android:layout_marginLeft="6dp"
        android:ellipsize="end"
        android:fontFamily="sans-serif-medium"
        android:maxLines="1"
        android:paddingBottom="6dp"
        android:textAllCaps="true"
        android:textColor="#000000"
        android:textSize="12sp"
        tools:text="Date" />

    <TextView
        android:id="@+id/primary_location"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/location_offset"
        android:fontFamily="sans-serif-condensed"
        android:paddingBottom="12dp"
        android:paddingLeft="12dp"
        android:paddingRight="12dp"
        android:text="Description"
        android:textAlignment="center"
        android:textColor="#757575"
        android:textSize="16sp" />

    <TextView
        android:id="@+id/date"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/primary_location"
        android:fontFamily="sans-serif-condensed"
        android:gravity="right"
        android:paddingBottom="16dp"
        android:paddingLeft="8dp"
        android:paddingRight="8dp"
        android:text="Mature"
        android:textColor="#424242"
        android:textSize="16sp" />


</RelativeLayout>

3 个答案:

答案 0 :(得分：0)

请尝试此功能获取位图

public Bitmap getBitmapfromUrl(String imageUrl) {
    try {
        URL url = new URL(imageUrl);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setDoInput(true);
        connection.connect();
        InputStream input = connection.getInputStream();
        Bitmap bitmap = BitmapFactory.decodeStream(input);
        return bitmap;

    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return null;

    }
}

答案 1 :(得分：0)

imageView您正在将图像加载为null。检查资源ID R.id.imageView是否正确。

答案 2 :(得分：0)

enter image description here你的链接工作完全正常..我正在使用Glide尝试这个。！阅读Glide Documentation 

compile 'com.squareup.picasso:picasso:2.5.2'

  compile 'com.github.bumptech.glide:glide:3.6.1'

    compile 'com.android.support:support-v4:25.1.0'

Glide  
    .with(context)
    .load(url)
    .override(200, 200) // resizes the image to these dimensions (in pixel). does not respect aspect ratio
    .into(imageView);

String url="http://api.androidhive.info/images/sample.jpg"

ProgressBar circular_progress;    circular_progress =（ProgressBar）findViewById（R.id.circularprogress）; 

Picasso.with(context).load(url).into(imageview);


    Glide.with(MainActivity.this)
            .load("http://books.google.com/books/content?id=JGQBcu5O_ZcC&printsec=frontcover&img=1&zoom=1&edge=curl&source=gbs_api")
    .listener(new RequestListener<String, GlideDrawable>() {
    @Override
    public boolean onException(Exception e, String model, Target<GlideDrawable> target, boolean isFirstResource) {
       circular_progress.setVisibility(View.GONE);
        return false;
    }

    @Override
    public boolean onResourceReady(GlideDrawable resource, String model, Target<GlideDrawable> target, boolean isFromMemoryCache, boolean isFirstResource) {
        circular_progress.setVisibility(View.GONE);
        return false;
    }
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