Android当点击按钮时实现全屏截图

Question

AndroidStudio，当点击MainActivity.java的activity_main.xml布局上的按钮btn时，实现全屏截图，截图保存到系统相册中。如何实现？

Answer 1

1.要在Android Studio中实现全屏截图并将其保存到系统相册中，您可以按照以下步骤进行操作：

确保您的应用程序具有适当的权限。在AndroidManifest.xml文件中添加以下权限：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

2.在MainActivity.java中，为按钮btn设置点击事件监听器，并在点击事件中执行截图和保存操作。以下是一个简单的示例代码：

import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.Canvas;
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.Toast;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_CODE_PERMISSION = 100;

    private Button btn;

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

        btn = findViewById(R.id.btn);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (hasWritePermission()) {
                    captureScreenshot();
                } else {
                    requestPermission();
                }
            }
        });
    }

    private boolean hasWritePermission() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            return ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED;
        }
        return true;
    }

    private void requestPermission() {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_CODE_PERMISSION);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == REQUEST_CODE_PERMISSION) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                captureScreenshot();
            } else {
                Toast.makeText(this, "Permission denied", Toast.LENGTH_SHORT).show();
            }
        }
    }

    private void captureScreenshot() {
        View rootView = getWindow().getDecorView().getRootView();
        Bitmap screenshot = Bitmap.createBitmap(rootView.getWidth(), rootView.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(screenshot);
        rootView.draw(canvas);

        try {
            File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "screenshot.png");
            FileOutputStream fos = new FileOutputStream(file);
            screenshot.compress(Bitmap.CompressFormat.PNG, 100, fos);
            fos.flush();
            fos.close();

            // 将截图添加到系统相册
            MediaStore.Images.Media.insertImage(getContentResolver(), file.getAbsolutePath(), file.getName(), null);

            Toast.makeText(this, "Screenshot saved", Toast.LENGTH_SHORT).show();
        } catch (IOException e) {
            e.printStackTrace();
            Toast.makeText(this, "Failed to save screenshot", Toast.LENGTH_SHORT).show();
        }
    }
}

3.在activity_main.xml布局文件中，添加一个按钮btn：

<Button
    android:id="@+id/btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Take Screenshot" />

以上代码将在点击按钮时执行截图并将其保存到系统相册中。请注意，您需要在Android设备上运行此应用程序，并且授予写入存储权限，以便截图能够成功保存到系统相册中。