隨筆

最近在做的一個項目中有用到從圖庫中選擇圖片，然后進行裁剪后再使用的功能，在這里也簡單的記錄下整個實現的過程，以備后查。

首先來看看布局文件，非常的簡單，兩個按鈕，一個ImageView.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical"
              android:padding="16dp">

    <Button
        android:id="@+id/take_photo_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:gravity="center"
        android:text="拍照"
        android:textSize="16sp"/>

    <Button
        android:id="@+id/select_photo_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:gravity="center"
        android:text="選擇圖片"
        android:textSize="16sp"/>

    <ImageView
        android:id="@+id/photo_iv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="20dp"/>
</LinearLayout>

然后再來看看代碼部分

package com.example.goblit.selectpic;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Intent;
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.os.Environment;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

import java.io.File;

public class SelectPicActivity extends Activity implements View.OnClickListener {
    private Button take_photo_btn;
    private Button select_photo_btn;
    private ImageView photo_iv;
    //使用照相機拍照獲取圖片
    public static final int TAKE_PHOTO_CODE = 1;
    //使用相冊中的圖片
    public static final int SELECT_PIC_CODE = 2;
    //圖片裁剪
    private static final int PHOTO_CROP_CODE = 3;
    //定義圖片的Uri
    private Uri photoUri;
    //圖片文件路徑
    private String picPath;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initViews();
    }

    private void initViews() {
        this.take_photo_btn = (Button) findViewById(R.id.take_photo_btn);
        this.take_photo_btn.setOnClickListener(this);
        this.select_photo_btn = (Button) findViewById(R.id.select_photo_btn);
        this.select_photo_btn.setOnClickListener(this);
        this.photo_iv = (ImageView) findViewById(R.id.photo_iv);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            //拍照
            case R.id.take_photo_btn:
                picTyTakePhoto();
                break;
            //選擇圖庫
            case R.id.select_photo_btn:
                pickPhoto();
                break;
        }
    }

    /**
     * 拍照獲取圖片
     */
    private void picTyTakePhoto() {
        //判斷SD卡是否存在
        String SDState = Environment.getExternalStorageState();
        if (SDState.equals(Environment.MEDIA_MOUNTED)) {
            Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);//"android.media.action.IMAGE_CAPTURE"
            /***
             * 使用照相機拍照，拍照后的圖片會存放在相冊中。使用這種方式好處就是：獲取的圖片是拍照后的原圖，
             * 如果不使用ContentValues存放照片路徑的話，拍照后獲取的圖片為縮略圖有可能不清晰
             */
            ContentValues values = new ContentValues();
            photoUri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);
            intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, photoUri);
            startActivityForResult(intent, TAKE_PHOTO_CODE);
        } else {
            Toast.makeText(this, "內存卡不存在", Toast.LENGTH_LONG).show();
        }
    }

    /***
     * 從相冊中取圖片
     */
    private void pickPhoto() {
        Intent intent = new Intent(Intent.ACTION_PICK, null);
        intent.setDataAndType(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                "image/*");
        startActivityForResult(intent, SELECT_PIC_CODE);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == Activity.RESULT_OK) {
            //從相冊取圖片，有些手機有異常情況，請注意
            if (requestCode == SELECT_PIC_CODE) {
                if (null != data && null != data.getData()) {
                    photoUri = data.getData();
                    picPath = uriToFilePath(photoUri);
                    startPhotoZoom(photoUri, PHOTO_CROP_CODE);
                } else {
                    Toast.makeText(this, "圖片選擇失敗", Toast.LENGTH_LONG).show();
                }
            } else if (requestCode == TAKE_PHOTO_CODE) {
                String[] pojo = {MediaStore.Images.Media.DATA};
                Cursor cursor = managedQuery(photoUri, pojo, null, null, null);
                if (cursor != null) {
                    int columnIndex = cursor.getColumnIndexOrThrow(pojo[0]);
                    cursor.moveToFirst();
                    picPath = cursor.getString(columnIndex);
                    if (Build.VERSION.SDK_INT < 14) {
                        cursor.close();
                    }
                }
                if (picPath != null) {
                    photoUri = Uri.fromFile(new File(picPath));
                    startPhotoZoom(photoUri, PHOTO_CROP_CODE);
                } else {
                    Toast.makeText(this, "圖片選擇失敗", Toast.LENGTH_LONG).show();
                }
            } else if (requestCode == PHOTO_CROP_CODE) {
                if (photoUri != null) {
                    Bitmap bitmap = BitmapFactory.decodeFile(picPath);
                    if (bitmap != null) {
                        //這里可以把圖片進行上傳到服務器操作
                        photo_iv.setImageBitmap(bitmap);
                    }
                }
            }
        }
    }

    private void startPhotoZoom(Uri uri, int REQUE_CODE_CROP) {
        Intent intent = new Intent("com.android.camera.action.CROP");
        intent.setDataAndType(uri, "image/*");
        // crop=true是設置在開啟的Intent中設置顯示的VIEW可裁剪
        intent.putExtra("crop", "true");
        // 去黑邊
        intent.putExtra("scale", true);
        intent.putExtra("scaleUpIfNeeded", true);
        // aspectX aspectY 是寬高的比例，根據自己情況修改
        intent.putExtra("aspectX", 1);
        intent.putExtra("aspectY", 1);
        // outputX outputY 是裁剪圖片寬高像素
        intent.putExtra("outputX", 100);
        intent.putExtra("outputY", 100);
        intent.putExtra("outputFormat", Bitmap.CompressFormat.JPEG.toString());
        //取消人臉識別功能
        intent.putExtra("noFaceDetection", true);
        //設置返回的uri
        intent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
        //設置為不返回數據
        intent.putExtra("return-data", false);
        startActivityForResult(intent, REQUE_CODE_CROP);
    }

    private String uriToFilePath(Uri uri) {
        //獲取圖片數據
        String[] proj = {MediaStore.Images.Media.DATA};
        //查詢
        Cursor cursor = managedQuery(uri, proj, null, null, null);
        //獲得用戶選擇的圖片的索引值
        int image_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToFirst();
        //返回圖片路徑
        return cursor.getString(image_index);
    }
}

整個選擇圖片并且裁剪的demo就寫好了，其實是非常的簡單。