本示例演示了如何在Android App中调整图像大小。
步骤1-在Android Studio中创建一个新项目,转到File⇒New Project并填写所有必需的详细信息以创建一个新项目。
步骤2-将以下代码添加到res / layout / activity_main.xml。
<? xml version= "1.0" encoding= "utf-8" ?> <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 :gravity= "center" tools :context= ".MainActivity" > <ImageView android :id= "@+id/ivImage" android :layout_width= "wrap_content" android :layout_height= "wrap_content" android :layout_centerHorizontal= "true" android :contentDescription= "@string/app_name" android :src= "@drawable/ic_launcher_foreground" /> <LinearLayout android :layout_width= "match_parent" android :layout_height= "wrap_content" android :layout_below= "@+id/ivImage" android :layout_centerHorizontal= "true" > <Button android :layout_width= "0dp" android :layout_height= "wrap_content" android :layout_marginTop= "8dp" android :layout_weight= "1" android :onClick= "uploadImage" android :text= "Upload Image" /> <Button android :layout_width= "0dp" android :layout_height= "wrap_content" android :layout_marginTop= "8dp" android :layout_weight= "1" android :onClick= "resizeImage" android :text= "Resize Image" /> </LinearLayout> </RelativeLayout>
步骤3-将以下代码添加到src / MainActivity.java
package app.(cainiaojc.com).sample ; import android.app.Activity ; import android.content.Intent ; import android.graphics.Bitmap ; import android.net.Uri ; import android.provider.MediaStore ; import android.support.v7.app.AppCompatActivity ; import android.os.Bundle ; import android.view.View ; import android.widget.ImageView ; import java.io.IOException ; public class MainActivity extends AppCompatActivity { ImageView ivImage ; public static final int PICK_IMAGE = 1 ; Bitmap yourBitmap ; @Override protected void onCreate (Bundle savedInstanceState) { super .onCreate(savedInstanceState) ; setContentView(R.layout. activity_main ) ; ivImage = findViewById(R.id. ivImage ) ; } public void uploadImage (View view) { Intent intent = new Intent(Intent. ACTION_GET_CONTENT ) ; intent.setType( "image/*" ) ; startActivityForResult(intent , PICK_IMAGE ) ; } public void resizeImage (View view) { Bitmap resized = Bitmap. createScaledBitmap ( yourBitmap , 400 , 400 , true ) ; ivImage .setImageBitmap(resized) ; } @Override public void onActivityResult ( int requestCode , int resultCode , Intent data) { super .onActivityResult(requestCode , resultCode , data) ; if (requestCode == PICK_IMAGE && resultCode == Activity. RESULT_OK ) { if (data == null ) { //显示错误 return; } try { Uri imageUri = data.getData() ; yourBitmap = MediaStore.Images.Media. getBitmap ( this .getContentResolver() , imageUri) ; ivImage .setImageBitmap( yourBitmap ) ; } catch (IOException e) { e.printStackTrace() ; } } } }
步骤4-将以下代码添加到androidManifest.xml
<? xml version= "1.0" encoding= "utf-8" ?> <manifest xmlns: android = "http://schemas.android.com/apk/res/android" package= "app.(cainiaojc.com).sample" > <application android :allowBackup= "true" android :icon= "@mipmap/ic_launcher" android :label= "@string/app_name" android :roundIcon= "@mipmap/ic_launcher_round" android :supportsRtl= "true" android :theme= "@style/AppTheme" > <activity android :name= ".MainActivity" > <intent-filter> <action android :name= "android.intent.action.MAIN" /> <category android :name= "android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>