无废话Android之smartimageview使用、android多线程下载、显式意图激活另外一个activity,检查网络是否可用定位到网络的位置、隐式意图激活另外一个activity、隐式意图

1.smartimageview使用 <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=".MainActivity" >    <com.loopj.android.image.SmartImageView android:id="@+id/iv_beauty" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_weight="100" />    <EditText android:id="@+id/et_path" android:layout_width="match_parent" android:layout_height="wrap_content" android:singleLine="true" android:text="http://a.hiphotos.baidu.com/album/w%3D2048/sign=0a938b00d53f8794d3ff4f2ee6230cf4/faedab64034f78f06fe0f24b78310a55b2191c9a.jpg" />    <Button android:layout_width="match_parent" android:layout_height="wrap_content" android:onClick="watch" android:text="浏览" /></LinearLayout>public class MainActivity extends Activity { private EditText et_path; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); this.et_path = (EditText) this.findViewById(R.id.et_path); } public void watch(View view) { String url = this.et_path.getText().toString().trim(); SmartImageView siv = (SmartImageView) this.findViewById(R.id.iv_beauty); siv.setImageUrl(url, R.drawable.ic_launcher, R.drawable.ic_launcher); } } <uses-permission android:name="android.permission.INTERNET"/>2.android多线程下载 public class MainActivity extends Activity { protected static final int SERVER_ERROR = 1; protected static final int DOWN_LOAD_ERROR = 2; protected static final int DOWN_LOAD_SUCCESS = 3; protected static final int UPDATE_TEXT = 4; private EditText et_path; private ProgressBar pb_download; private TextView tv_process; private static int threadCount = 3; private static int runningThread = threadCount; private static int currentProgress = 0; private static String resource = "/mnt/sdcard/oracle.pptx"; private static String path = "http://110.65.99.66:8080/oracle.pptx"; private static String mode = "rwd"; private Handler handler = new Handler() { @Override public void handleMessage(Message msg) { switch (msg.what) { case SERVER_ERROR: Toast.makeText(MainActivity.this, "服务器错误，错误码：" + (String) msg.obj, 0).show(); break; case DOWN_LOAD_ERROR: Toast.makeText(MainActivity.this, "下载失败", 0).show(); break; case DOWN_LOAD_SUCCESS: Toast.makeText(MainActivity.this, "文件下载完毕，临时文件被删除!", 0).show(); break; case UPDATE_TEXT: tv_process.setText("当前进度：" + pb_download.getProgress() * 100                        / pb_download.getMax()); break; } } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); this.et_path = (EditText) this.findViewById(R.id.et_path); this.pb_download = (ProgressBar) this.findViewById(R.id.pb_download); this.tv_process = (TextView) this.findViewById(R.id.tv_process); } public void download(View view) { new Thread() { public void run() { try { // 连接服务器获取一个文件，在本地创建一个和它相同大小的临时文件                    URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection) url .openConnection(); conn.setRequestMethod("GET"); conn.setConnectTimeout(5000); int code = conn.getResponseCode(); if (code == 200) { // 服务器返回的数据长度，实际上就是文件的长度                        int length = conn.getContentLength(); System.out.println("文件的长度 ：" + length); // 设置进度条的最大值                        pb_download.setMax(length - 1); // 在本地创建一个大小跟服务器文件一样大小的临时文件                        RandomAccessFile raf = new RandomAccessFile(resource, mode); // 指定文件的长度 raf.setLength(length); raf.close(); // 假设是3个线程去下载资源 // 计算平均每个线程下载的文件大小                        int blockSize = length / threadCount; // 标记正在运行子线程的个数                        runningThread = threadCount; // 下载进度归零                        currentProgress = 0; // 下载进度条归零                        pb_download.setProgress(0); System.out.println("blockSize = " + blockSize); for (int threadId = 1; threadId <= threadCount; threadId++) { // 线程的开始和结束位置                            int startIndex = (threadId - 1) * blockSize; int endIndex = threadId * blockSize - 1; if (threadId == threadCount) { endIndex = length - 1; } System.out.println("线程：" + threadId + "下载："                                    + startIndex + "--->" + endIndex); new DownLoadThread(threadId, startIndex, endIndex, path).start(); } } else { Message msg = new Message(); msg.what = SERVER_ERROR; msg.obj = code + ""; handler.sendMessage(msg); } } catch (Exception e) { e.printStackTrace(); Message msg = new Message(); msg.what = DOWN_LOAD_ERROR; handler.sendMessage(msg); } }; }.start(); } public class DownLoadThread extends Thread { private int threadId; private int startIndex; private int endIndex; private String path; private String tempFileUrl; public DownLoadThread(int threadId, int startIndex, int endIndex, String path) { this.threadId = threadId; this.startIndex = startIndex; this.endIndex = endIndex; this.path = path; tempFileUrl = "/mnt/sdcard/" + threadId + ".txt"; } @Override public void run() { try { // 检查是否存在记录下载长度的文件，如果存在读取这个文件的数据                File tempFile = new File(tempFileUrl); if (tempFile.exists() && tempFile.length() > 0) { FileInputStream fis = new FileInputStream(tempFile); byte[] buffer = new byte[1024]; int length = fis.read(buffer); String downloadLength = new String(buffer, 0, length); int downloadLenInt = Integer.parseInt(downloadLength); int alreayDownloadInt = downloadLenInt - startIndex; currentProgress += alreayDownloadInt;// 计算上次断点下载到的进度 // 修改下载的真实开始位置                    startIndex = downloadLenInt; fis.close(); } System.out.println("线程真正开始的位置 ：" + threadId + "下载："                        + startIndex + "--->" + endIndex); URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection) url .openConnection(); conn.setRequestMethod("GET"); conn.setConnectTimeout(5000); // 请求服务器下载部分文件，指定文件的位置                conn.setRequestProperty("Range", "bytes=" + startIndex + "-"                        + endIndex); conn.setConnectTimeout(60000); // 200表示从服务器请求全部资源，206表示从服务器请求部分资源                int code = conn.getResponseCode(); if (code == 206) { // 已经设置了请求的位置，返回的是当前文件位置对应的文件的输入流                    InputStream is = conn.getInputStream(); // 此类的实例支持对随机访问文件的读取和写入                    RandomAccessFile raf = new RandomAccessFile(resource, mode); // 定位文件 raf.seek(startIndex); int length = 0; byte[] buffer = new byte[1024]; int total = 0;// 实时记录已经下载的长度 // 一阵狂读                    while ((length = is.read(buffer)) != -1) { RandomAccessFile file = new RandomAccessFile( tempFileUrl, mode); raf.write(buffer, 0, length); total += length; // 记录当前线程下载的数据位置                        file.write((total + startIndex - 1 + "").getBytes()); file.close(); synchronized (MainActivity.this) { // 获取所有线程下载的总进度                            currentProgress += length; // 更改界面上progressbar的进度(progressbar和progressdialog可以在子线程里修改UI) pb_download.setProgress(currentProgress); Message msg = Message.obtain(); msg.what = UPDATE_TEXT; handler.sendMessage(msg); } } raf.close(); is.close(); System.out.println("线程 ： " + threadId + "下载完毕。。。。。"); runningThread--; } else { System.out.println("线程 ： " + threadId + "下载失败。。。。。"); } } catch (Exception e) { e.printStackTrace(); System.out.println("线程 ： " + threadId + "  抛出异常！"); runningThread = threadCount; } finally { System.out.println("runningThread = " + runningThread); if (runningThread == 0) { for (int i = 1; i <= threadCount; i++) { File deleteFile = new File("/mnt/sdcard/" + i + ".txt"); deleteFile.delete(); } Message msg = new Message(); msg.what = DOWN_LOAD_SUCCESS; handler.sendMessage(msg); } } } } } 3.显式意图激活另外一个activity,检查网络是否可用定位到网络的位置 <intent-filter>    <action android:name="android.intent.action.MAIN" />    <category android:name="android.intent.category.LAUNCHER" /></intent-filter> 这段代码的作用是告诉系统在桌面创建一个快捷图标 <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:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" >    <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:onClick="click1" android:text="跳转到第二个界面1" />    <Button android:id="@+id/button2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignRight="@+id/button1" android:layout_below="@+id/button1" android:layout_marginTop="24dp" android:onClick="click2" android:text="跳转到第二个界面2" />    <Button android:id="@+id/button3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/button2" android:layout_below="@+id/button2" android:layout_marginLeft="44dp" android:layout_marginTop="27dp" android:onClick="click3" android:text="检查手机网络状态" />    <Button android:id="@+id/button4" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/button2" android:layout_below="@+id/button3" android:layout_marginLeft="16dp" android:layout_marginTop="37dp" android:onClick="click4" android:text="跳转到图库" /></RelativeLayout>public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void click1(View view) { Intent intent = new Intent(); intent.setClassName(this, "com.itheima.explicitintent.SecondActivity"); this.startActivity(intent); } public void click2(View view) { Intent intent = new Intent(this, SecondActivity.class); this.startActivity(intent); } public void click3(View view) { ConnectivityManager manager = (ConnectivityManager) this .getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo info = manager.getActiveNetworkInfo(); if (info != null && info.isAvailable()) { Toast.makeText(this, "网络可用", 0).show(); } else { Toast.makeText(this, "网络不可用", 0).show(); Intent intent = new Intent(); intent.setClassName("com.android.phone", "com.android.phone.MiuiSettings"); this.startActivity(intent); } } public void click4(View view) { Intent intent = new Intent(); intent.setClassName("com.miui.gallery", "com.miui.gallery.app.Gallery"); this.startActivity(intent); } } <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>4.隐式意图激活另外一个activity，即打开另外一个app的activity public void click(View view) { Intent intent = new Intent(); intent.setAction(Intent.ACTION_VIEW); intent.setData(Uri.parse("http://www.baidu.com")); this.startActivity(intent); } public void send(View view) { Intent intent = new Intent(); intent.setAction(Intent.ACTION_SENDTO); intent.setData(Uri.parse("sms:10086")); intent.addCategory("android.intent.category.DEFAULT"); this.startActivity(intent); } 5.隐式意图的配置，自定义隐式意图 第一个activity启动第二个activity 第一个Activity public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void click(View view) { Intent intent = new Intent(); intent.setAction("com.itheima.secondActivity"); // 额外信息，提供一些执行的环境参数        intent.addCategory("android.intent.category.DEFAULT"); intent.setDataAndType(Uri.parse("itheima:jerry"), "vnd.android.cursor.item/mp3"); this.startActivity(intent); } } 第二个Activity public class SecondActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_second); Intent intent = this.getIntent(); Uri uri = intent.getData(); String data = uri.toString(); String type = intent.getType(); Toast.makeText(this, "data = " + data + " , type = " + type, 0).show(); } } <activity android:name=".SecondActivity" android:label="@string/app_name" >    <intent-filter>        <action android:name="com.itheima.secondActivity"/>        <category android:name="android.intent.category.DEFAULT"/>        <data android:scheme="itheima" android:mimeType="vnd.android.cursor.item/mp3"/>    </intent-filter></activity>6.隐式意图和显示意图的使用场景 同一个应用程序里面，自己激活自己的东西，推荐使用显示意图，效率高 不同的应用程序里面，激活别人的应用，或者是让自己的某一个界面希望被别人激活，推荐使用隐式意图。 7.在不同activity之间数据传递 public void click(View view) { String name = this.et_name.getText().toString().trim(); if (TextUtils.isEmpty(name)) { Toast.makeText(this, "姓名不能为空", 0).show(); return; } Intent intent = new Intent(this, ResultActivity.class); intent.putExtra("name", name); this.startActivity(intent); } 接收数据 protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_result); TextView tv_result = (TextView) this.findViewById(R.id.tv_result); Intent intent = this.getIntent(); String name = intent.getStringExtra("name"); Random random = new Random(); int rp = random.nextInt(101); tv_result.setText(name + "的人品为：" + rp); }
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