"Android" read the picture on the SDcard

Android reads the picture on the sdcard is very simple thing, below uses an example to illustrate this question.

First of all, there's a img25.jpg on the sdcard that's ready.

Below, what needs to be done is to read this image into the app display. Achieve the following effects:

1, first you want to apply to read SDcard permission in Androidmanifest.xml, after adding a statement, androidmanifest.xml as follows:

<?xml version= "1.0" encoding= "Utf-8"? ><manifest xmlns:android= "http://schemas.android.com/apk/res/ Android "package=" Com.sdcardread "android:versioncode=" 1 "android:versionname=" 1.0 "> <uses-sdk A ndroid:minsdkversion= "8" android:targetsdkversion= "/> <uses-permission android:name=" Android.permissio N.write_external_storage "/> <!--write data to SDcard right--<application android:allowbackup=" true "a        ndroid:icon= "@drawable/ic_launcher" android:label= "@string/app_name" android:theme= "@style/apptheme" >            <activity android:name= "com.sdcardread.MainActivity" android:label= "@string/app_name" > <intent-filter> <action android:name= "Android.intent.action.MAIN"/> & Lt;category android:name= "Android.intent.category.LAUNCHER"/> </intent-filter> &LT;/ACTIVITY&G    T </application></manifest> 

2, after res\values\strings.xml modify this app name called "Picture read", this step can not do, just for the program more beautiful.

<?xml version= "1.0" encoding= "Utf-8"?><resources> <string    name= "app_name" > Picture read </string >    <string name= "Action_settings" >Settings</string></resources>

3, second in the res\layout\activity_main.xml to decorate a textview with ID, a moment of prompt information will be written to this textview, at the same time decorate a linear layout with the ID. The image will be added to this linear layout for a while.

<linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android" Android:layout_width= "Match_parent" android:layout_height= "match_parent" android:orientation= "vertical" > < TextView android:id= "@+id/textview1" android:layout_width= "wrap_content" android:layout_height= "Wrap_ Content "android:textsize=" 24sp "/> <textview android:layout_width=" Wrap_content "Android:la         yout_height= "Wrap_content" android:textsize= "24sp"/> <linearlayout android:id= "@+id/linearlayout1" Android:layout_width= "Match_parent" android:layout_height= "wrap_content" android:orientation= "Horizo Ntal "> </linearlayout></linearlayout> 

4, the core of the entire program in Mainactivity.java, code as follows, get the component, first use Environment.getexternalstoragestate (). Equals (Environment.media_ mounted); Determine if sdcard exists, then use Environment.getexternalstoragedirectory (). GetAbsolutePath (); Gets the absolute path of the sdcard for read by the Java file class. Finally, a ImageView object is created and loaded into the linear layout linearLayout1.

Package Com.sdcardread;import Java.io.file;import Android.os.bundle;import android.os.environment;import Android.widget.imageview;import Android.widget.linearlayout;import Android.widget.textview;import Android.app.activity;import Android.graphics.bitmap;import Android.graphics.bitmapfactory;public Class Mainactivity extends Activity {private TextView textview1;private linearlayout linearLayout1; @Overrideprotected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate); Setcontentview (R.layout.activity_main); TextView1 = (TextView) Findviewbyid (r.id.textview1); linearLayout1 = (linearlayout) Findviewbyid (R.ID.LINEARLAYOUT1); Boolean issdcardexist = Environment.getexternalstoragestate (). Equals (environment.media_mounted);//Determine if sdcard exists if ( issdcardexist) {String Sdpath = Environment.getexternalstoragedirectory (). GetAbsolutePath ();// Gets the root path of the SDcard textview1.settext ("SD card is present. The following is the img25.jpg! under SDcard "); String filepath = sdpath + file.separator + "img25.jpg"; File File = new file (filepath); ImageView ImageView = new ImageView (this);//Create a ImageView object if (file.exists ()) {Bitmap BM = Bitmapfactory.decodefile (filepath);//Display the picture in ImageView Imageview.setimagebitmap (BM); Linearlayout1.addview ( ImageView);}} else {textview1.settext ("SD card does not exist!) ");}}}

"Android" read the picture on the SDcard