1.smartimageview使用
<LinearLayout xmlns:andro>
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:andro>
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);
}
