ProgressBar進度條， 分為旋轉進度條和水平進度條，進度條的樣式根據需要自定義，之前一直不明白進度條如何在實際項目中使用，網上演示進度條的案例大多都是通過Button點 擊增加、減少進度值，使用方法incrementProgressBy(int)，最簡單的做法是在xml布局文件中放置ProgressBar空間，然 后再MainActivity中觸發事件后執行incrementProgressBy(int)，代碼如下：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

<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" ????tools:context="cn.teachcourse.www.MainActivity" ????android:orientation="vertical" ????android:gravity="center" ????android:id="@+id/onclick_ll" > <!--點擊LinearLayout控件，改變ProgressBar進度--> ????<ProgressBar ????????android:id="@+id/progressBar_horizontal" ????????style="?android:attr/progressBarStyleHorizontal" ????????android:layout_width="match_parent" ????????android:layout_height="15dp" ????????android:layout_marginTop="28dp"/> </LinearLayout>

在Java代碼中非常的簡單，如下圖：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

public class MainActivity extends ActionBarActivity implements View.OnClickListener{ ????private ProgressBar pb_large; ????private ProgressBar pb_normal; ????private ProgressBar pb_small; ????private ProgressBar pb_horizontal; ????private int readed; ????private int progressValue; ????? ????private LinearLayout onclick_ll; ????@Override ????protected void onCreate(Bundle savedInstanceState) { ????????super.onCreate(savedInstanceState); ????????setContentView(R.layout.activity_main); ????????initView(); ????????Drawable drawable = getResources().getDrawable( ????????????????R.drawable.progress_bar_states); ????????pb_horizontal.setProgressDrawable(drawable);//設置水平滾動條的樣式 ?????????? ????????pb_horizontal.setMax(100);//設置進度條的最大值?????? ????????onclick_ll.setOnClickListener(this);//LinearLayout添加監視器 ????} ????private void initView() {?????? ????????pb_horizontal = (ProgressBar) findViewById(R.id.progressBar_horizontal); ????????onclick_ll=(LinearLayout)findViewById(R.id.onclick_ll); ????} ????@Override ????public void onClick(View v) { ????????pb_horizontal.incrementProgressBy(5);?????? ????????if(pb_horizontal.getProgress()==pb_horizontal.getMax()){ ????????????Toast.makeText(this, "進度條已經達到最大值,進度條消失", Toast.LENGTH_LONG).show(); ????????????pb_horizontal.setProgress(0);?? //當達到最大之后，進度值歸0???? ????????} ????} }

我們這里展示的是ProgressBar讀取文件字節流后，展示的讀取進度條，上面的簡單演示就不說了。第一張效果圖：

第二張效果圖：

?第三張效果圖：

?第四張效果圖

這里展示文件讀取字節流過程中，ProgressBar進度變化情況，當讀取完成，進度條剛好滿，這在我們實際項目開發中，經常需要使用到，如何成為我寫這篇文章的原因。
布局文件progress_horizontal_read_data.xml

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

<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" ????tools:context="cn.teachcourse.www.MainActivity" ????android:orientation="vertical" ????android:gravity="center" > <TextView ????android:layout_width="match_parent" ????android:layout_height="wrap_content" ????android:layout_weight="1" ????android:id="@+id/read_data_tv" ????android:text="@string/read_info" ????android:scrollbars="vertical" ????android:layout_marginLeft="10dp" ????android:layout_marginRight="10dp" ????android:lineSpacingExtra="10dp"/> ??? ????<ProgressBar ????????android:id="@+id/progressBar_horizontal_read_data" ????????style="?android:attr/progressBarStyleHorizontal" ????????android:layout_width="match_parent" ????????android:layout_height="15dp" ????????android:layout_marginTop="28dp"/> </LinearLayout>

Java代碼ProgressBarActivity.java

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97

public class ProgressBarActivity extends ActionBarActivity { ????private ProgressBar pb_horizontal; ????private int readed; ????private int progressValue; ????private TextView mReadProgress_TV; ????private String mData; ????private StringBuffer sb;//每次讀取到的字節數據存儲 ????int length;//標記文件大小 ????private Thread thread;//讀取文件線程 ????@Override ????protected void onCreate(Bundle savedInstanceState) { ????????super.onCreate(savedInstanceState); ????????setContentView(R.layout.progress_horizontal_read_data); ????????initView(); ????????Drawable drawable = getResources().getDrawable( ????????????????R.drawable.progress_bar_states); ????????String path = Environment.getExternalStorageDirectory() ????????????????+ "/ProgressMonitor.txt";// ProgressMonitor.txt是我存到sdcard中的一個文件，可以自定義文件名大小位置 ????????final File file = new File(path); ????????? ????????if(file.exists()){ ????????????length=(int) file.length(); ????????????pb_horizontal.setMax(length);//設置進度條最大值 ????????????pb_horizontal.setProgressDrawable(drawable);//自定義進度條樣式 ????????} ????????//啟動一個線程讀取文件內容 ????????thread=new Thread() { ????????????@Override ????????????public void run() { ????????????????readFromFile(file.getAbsolutePath()); ????????????} ????????}; ????????thread.start(); ????} ????Handler handler = new Handler() { ????????@Override ????????public void handleMessage(Message msg) { ????????????switch (msg.what) { ????????????case 110: ????????????????progressValue += msg.arg1; ????????????????pb_horizontal.setProgress(progressValue); ????????????????mReadProgress_TV.setText(sb.toString()); ????????????????if(progressValue==length){ ????????????????????Toast.makeText(ProgressBarActivity.this, "文件讀取完成", Toast.LENGTH_LONG).show(); ????????????????} ????????????????Log.d("progressValue-------------->", progressValue + ""); ????????????????break; ????????????} ????????} ????}; ????public void readFromFile(String path) { ????????FileInputStream fis; ????????try { ????????????fis = new FileInputStream(path); ????????????DataInputStream dis = new DataInputStream(fis); ?????????????????sb=new StringBuffer(); ????????????byte b[] = new byte[10];// 每次讀取1字節 ????????????while ((readed = dis.read(b)) != -1) { ????????????????Message msg = new Message(); ????????????????msg.arg1 = readed;????????????? ????????????????msg.what = 110; ????????????????mData=new String(b,0,readed); ????????????????sb.append(mData); ????????????????handler.sendMessage(msg); ????????????????try { ????????????????????Thread.sleep(1000); ????????????????} catch (Exception e) { ????????????????????// TODO Auto-generated catch block ????????????????????e.printStackTrace(); ????????????????} ????????????} ????????????dis.close(); ????????????fis.close(); ????????} catch (Exception e) { ????????????? ????????????e.printStackTrace(); ????????} ????} ????private void initView() { ????????pb_horizontal = (ProgressBar) findViewById(R.id.progressBar_horizontal_read_data); ????????mReadProgress_TV=(TextView)findViewById(R.id.read_data_tv); ????} }

這里使用Handler消息處理，每次讀取到數據后更新進度條，將讀取的字節數據放置在arg1中，在Handler的handleMessage 方法中設置進度值，同時刷新TextView顯示的內容，這里難就難在如何獲取每次讀取的字節數，然后刷新進度條，在字節流的學習中，我們可以自定義每次 讀取字節大小，File類中可以獲取到文件的總大小，如果不明白字節流的操作的，可以查看《Java開發基礎之文件流操作解析》，最終我們得到上面圖片中 的效果。在這個例子里面，我們可以將讀取手機卡的文件，換成下載文件，傳輸文件同樣適應。

轉載于:https://www.cnblogs.com/dazhao/p/4943569.html

總結

以上是生活随笔為你收集整理的Android之ProgressBar读取文件进度解析的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。