java - 来自网络的 Android 图片

Question

我正在开发一个简单的货币转换器应用程序，我想通过 URL 从网络上获取图像。我使用过许多教程，但似乎没有一个能够工作，即使是简单的复制和粘贴而不进行修改。我的 XML 中是否存在问题，或者只是我的 java 代码中存在愚蠢的错误？

XML imageView 位于最底部，我只是将其与默认图标图像一起放置，但当我运行应用程序时它不会显示。

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#FFFFFF"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/Title"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="26dp"
        android:gravity="center"
        android:text="Currency Converter"
        android:textColor="#06BD27"
        android:textSize="24dp" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:layout_below="@+id/Title"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="53dp"
        android:text="Enter an Amount:" />

    <Spinner
        android:id="@+id/spinner1"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/editText1"
        android:layout_below="@+id/editText1"
        android:layout_marginTop="82dp"
        android:entries="@array/To"
        android:prompt="@string/ToCurrent" />

    <Spinner
        android:id="@+id/spinner2"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/spinner1"
        android:layout_below="@+id/editText1"
        android:layout_marginTop="23dp"
        android:entries="@array/From"
        android:prompt="@string/FromCurrent" />

    <EditText
        android:id="@+id/editText2"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/spinner1"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="18dp" />

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/spinner1"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="66dp"
        android:src="@drawable/ic_launcher" />

</RelativeLayout>

Java 代码 createDrawableFromURL() 应该处理图像

package com.kimberly.currency_convertor;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;



import android.app.Activity;
import android.graphics.Typeface;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.Spinner;
import android.widget.TextView;

public class CurrentConvert extends Activity
{
    Spinner FirstSpin, SecondSpin;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.converter);

        FirstSpin = (Spinner)findViewById(R.id.spinner1);
        SecondSpin = (Spinner)findViewById(R.id.spinner2);

        TextView MainTitle = (TextView) findViewById(R.id.Title);  
        Typeface Currency = Typeface.createFromAsset(getAssets(), "CURRENCY.TTF"); 
        MainTitle.setTypeface(Currency); 

        ImageView imageView = (ImageView)findViewById(R.id.imageView1);
        imageView.setImageDrawable(createDrawableFromURL("http://savagelook.com/misc/sl_drop2.png"));
    }

    private Drawable createDrawableFromURL(String urlString) 
    {
        Drawable image = null;
    try 
    {
        URL url = new URL(urlString);
        InputStream is = (InputStream)url.getContent();
        image = Drawable.createFromStream(is, "src");
    } 
    catch (MalformedURLException e) 
    {
        // handle URL exception
        image = null;
    } catch (IOException e) 
    {
        // handle InputStream exception
        image = null;
    }

    return image;
    }
}

这是我一直试图遵循的代码 http://savagelook.com/blog/android/display-images-from-the-internet-in-android

Answer 1

只需使用BufferedImage image = ImageIO.getImage(URL)。