團隊專案——和諧共生（7）
阿新 • • 發佈：2022-05-10
距離上次發部落格的時間有些久了，這次要實現的功能是Android呼叫系統相簿
要實現這一功能，首先加入許可權
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />然後是編寫介面
<?xml version="1.0" encoding="utf-8"?> <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"android:layout_height="match_parent" tools:context=".MainActivity"> <Button android:id="@+id/choose_photo" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:text="從相簿中選擇照片" android:textSize="20sp" app:layout_constraintTop_toTopOf="parent" /> <ImageView android:id="@+id/picture" android:layout_width="0dp" android:layout_height="wrap_content" android:src="@drawable/shuishan" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" /> </androidx.constraintlayout.widget.ConstraintLayout>
最後是後臺程式碼
package com.example.pictureselect; import androidx.annotation.NonNull; import androidx.annotation.Nullable; import androidx.annotation.RequiresApi; import androidx.appcompat.app.AppCompatActivity; import androidx.core.app.ActivityCompat; import androidx.core.content.ContextCompat; import android.Manifest; import android.annotation.SuppressLint; import android.content.ContentUris; import android.content.Intent; import android.content.SharedPreferences; import android.content.pm.PackageManager; import android.database.Cursor; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.net.Uri; import android.os.Build; import android.os.Bundle; import android.provider.DocumentsContract; import android.provider.MediaStore; import android.view.View; import android.widget.Button; import android.widget.ImageView; import android.widget.Toast; public class MainActivity extends AppCompatActivity { public static final int CHOOSE_PHOTO = 2; ImageView picture; String imagePath = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button btnChoosePhoto = (Button) findViewById(R.id.choose_photo); picture = (ImageView) findViewById(R.id.picture); btnChoosePhoto.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { requestPermissino(); } }); picture.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { requestPermissino(); } }); } private void requestPermissino() { if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1); }else { openAlbum(); } } private void openAlbum(){ Intent intent = new Intent("android.intent.action.GET_CONTENT"); intent.setType("image/*"); startActivityForResult(intent,CHOOSE_PHOTO); //開啟相簿 } @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { super.onRequestPermissionsResult(requestCode, permissions, grantResults); switch (requestCode){ case 1: if (grantResults.length>0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){ openAlbum(); }else { Toast.makeText(this,"你拒絕了該許可權",Toast.LENGTH_SHORT).show(); } break; default: break; } } @Override protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) { super.onActivityResult(requestCode, resultCode, data); switch (requestCode){ case CHOOSE_PHOTO: if(resultCode == RESULT_OK){ //判斷手機系統版本號 if(Build.VERSION.SDK_INT>=19){ //4.4及以上系統使用這個方法處理圖片 handleImageOnKitKat(data); } } break; default: break; } } @RequiresApi(api = Build.VERSION_CODES.KITKAT) private void handleImageOnKitKat(Intent data){ Uri uri = data.getData(); if(DocumentsContract.isDocumentUri(this,uri)){ //如果是document型別的Uri，則通過document id處理 String docId = DocumentsContract.getDocumentId(uri); if("com.android.providers.media.documents".equals(uri.getAuthority())){ String id = docId.split(":")[1]; //解析出數字格式的id String selection = MediaStore.Images.Media._ID+"="+id; imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,selection); }else if("com.android.providers.downloads.documents".equals(uri.getAuthority())){ Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public downloads"),Long.valueOf(docId)); imagePath = getImagePath(contentUri,null); } }else if("content".equalsIgnoreCase(uri.getScheme())){ //如果是file型別的Uri，直接獲取圖片路徑即可 imagePath = getImagePath(uri,null); }else if("file".equalsIgnoreCase(uri.getScheme())){ //如果是file型別的Uri，直接獲取圖片路徑即可 imagePath = uri.getPath(); } displayImage(imagePath); //根據圖片路徑顯示圖片 } //將選擇的圖片Uri轉換為路徑 @SuppressLint("Range") private String getImagePath(Uri uri, String selection){ String path = null; //通過Uri和selection來獲取真實的圖片路徑 Cursor cursor = getContentResolver().query(uri,null,selection,null,null); if(cursor!= null){ if(cursor.moveToFirst()){ path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA)); } cursor.close(); } return path; } //展示圖片 private void displayImage(String imagePath){ if(imagePath!=null && !imagePath.equals("")){ Bitmap bitmap = BitmapFactory.decodeFile(imagePath); picture.setImageBitmap(bitmap); //儲存上次選擇的圖片路徑，用以再次開啟app設定圖片 SharedPreferences sp = getSharedPreferences("sp_img",MODE_PRIVATE); //建立xml檔案儲存資料，name:建立的xml檔名 SharedPreferences.Editor editor = sp.edit(); //獲取edit() editor.putString("imgPath",imagePath); editor.apply(); }else { Toast.makeText(this,"獲取圖片失敗",Toast.LENGTH_SHORT).show(); } } @Override protected void onResume() { super.onResume(); //設定再次app時顯示的圖片 SharedPreferences sp = getSharedPreferences("sp_img", MODE_PRIVATE); //取出上次儲存的圖片路徑設定此次的圖片展示 String beforeImagePath = sp.getString("imgPath", null); displayImage(beforeImagePath); } }
到此為止，這個功能就實現了，但不足的是他一次只能獲取一張圖片，之後會再進行優化。