foodcheck/network.java

package com.example.health;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.core.content.FileProvider;
import android.Manifest;
import android.annotation.SuppressLint;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.provider.MediaStore;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
public class network extends AppCompatActivity {
    protected static final int CHANGE_UI = 1;
    protected static final int ERROR = 2;
    private static final int REQUEST_CODE_TAKE = 1;
    private Uri imageUri;
    private ImageView ivPic;

    @SuppressLint("HandlerLeak")
    private Handler handler = new Handler(){
        public void handleMessage(android.os.Message msg){
            if (msg.what == CHANGE_UI){
                Bitmap bitmap = (Bitmap) msg.obj;
                ivPic.setImageBitmap(bitmap);
            }
            else if (msg.what == ERROR){
                Toast.makeText(network.this,"显示图片错误",Toast.LENGTH_SHORT).show();
            }
        }
    };


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_network);
        ivPic = (ImageView) findViewById(R.id.iv_pic);
    }

    public  void click(View view){
            new Thread(){
                private HttpURLConnection conn;
                private  Bitmap bitmap;
                public void run(){
                    try{
                        URL url = new URL("https://picb2.photophoto.cn/40/293/40293462_1.jpg");
                        conn = (HttpURLConnection) url.openConnection();
                        conn.setRequestMethod("GET");
                        conn.setConnectTimeout(5000);
                        int code = conn.getResponseCode();
                        if(code == 200){
                            InputStream is = conn.getInputStream();
                            bitmap = BitmapFactory.decodeStream(is);
                            Message msg = new Message();
                            msg.what = CHANGE_UI;
                            msg.obj = bitmap;
                            handler.sendMessage(msg);
                        }
                        else{
                            Message msg = new Message();
                            msg.what = ERROR;
                            handler.sendMessage(msg);
                        }

                    }
                    catch(Exception e){
                        e.printStackTrace();
                        Message msg = new Message();
                        msg.what = ERROR;
                        handler.sendMessage(msg);
                    }
                    conn.disconnect();
                }
            }.start();
        }

    public void takephoto(View view) {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
            // 真正的执行去拍照
            doTake();
        } else {
            // 去申请权限
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, 1);
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == 1) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                doTake();
            } else {
                Toast.makeText(this, "你没有获得摄像头权限~", Toast.LENGTH_SHORT).show();
            }
        }

    }

    private void doTake() {
        File imageTemp = new File(getExternalCacheDir(), "imageOut.jpeg");
        if (imageTemp.exists()) {
            imageTemp.delete();
        }
        try {
            imageTemp.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();
        }

        if (Build.VERSION.SDK_INT > 24) {
            // contentProvider
            imageUri = FileProvider.getUriForFile(this, "com.example.health.fileprovider", imageTemp);
        } else {
            imageUri = Uri.fromFile(imageTemp);
        }
        Intent intent = new Intent();
        intent.setAction("android.media.action.IMAGE_CAPTURE");
        intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
        startActivityForResult(intent, REQUEST_CODE_TAKE);

    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE_TAKE) {
            if (resultCode == RESULT_OK) {
                // 获取拍摄的照片
                try {
                    InputStream inputStream = getContentResolver().openInputStream(imageUri);
                    Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                    ivPic.setImageBitmap(bitmap);
                } catch (FileNotFoundException e) {

                }
            }
        }
    }
}