Question

我正在尝试从URL下载图像到SD卡。为了执行此任务，我在我的应用程序中添加了Picasso库，并尝试使用此代码将图像下载到SD卡：

package com.example.imagedownloadsample;

import java.io.File;

import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.Button;

import com.squareup.picasso.Picasso;
import com.squareup.picasso.Target;

public class MainActivity extends ActionBarActivity {

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

        Button bn = (Button) findViewById(R.id.button1);
        bn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                // do something to download images to sd card

                File file = new File(Environment.getExternalStorageDirectory(),
                        "Android/data/com.usd.pop");
                file.mkdirs();
                Picasso.with(context).load("your URL").into(file);

            }
        });

    }

}

但是我收到了这个错误：

描述资源路径位置类型上下文无法解析为变量MainActivity.java / ImageDownloadSample / src / com / example / imagedownloadsample第31行Java问题

Answer 1

动态的方式：

Picasso.with(getApplicationContext()).load("your URL").into(file);

Answer 2

尝试替换此代码，希望这有助于您解决问题。

public class MainActivity extends ActionBarActivity {

    private Context context;
    private Button bn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.image_download);
        context = this;
        bn = (Button) findViewById(R.id.button1);
        bn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do something to download images to sd card

                File file = new File(Environment.getExternalStorageDirectory(),
                        "Android/data/com.usd.pop");
                file.mkdirs();
                Picasso.with(context).load("your URL").into(file);
            }
        });
    }
}

毕加索上下文无法解析为变量

2 个答案: