java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法“void android.widget.ImageView.setImageResource(int)" [英] java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageResource(int)' on a null object reference

问题描述

java.lang.NullPointerException: 尝试在空对象引用上调用虚方法void android.widget.ImageView.setImageResource(int)"

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageResource(int)' on a null object reference

我想让第一个活动的图标/图像转移或移动到第二个活动，但出现上述错误.

I want to make the icon/image of the first activity transfer or move to the second activity but this error above show up.

这是我在第一个活动中的源代码:

This is my source code in the first actvty:

 public void next (View view){
    Intent intent = new Intent(this, Products.class);
    intent.putExtra("Button ID", btnId);
    startActivity(intent);
}

然后在第二个活动中

 btnId = getIntent().getIntExtra("Button ID", btnId);
    setContentValues();
}

private void setContentValues() {
    ImageView titleImg = (ImageView) findViewById(R.id.imageView_result_title);
    View view = (View)findViewById(R.id.layout_goals_goals);

    switch (btnId) {
        case R.id.imageButton_goals_car:
            titleImg.setImageResource(R.drawable.car);
            break;
        case R.id.imageButton_goals_education:
            titleImg.setImageResource(R.drawable.education);
            break;
        case R.id.imageButton_goals_health:
            titleImg.setImageResource(R.drawable.health);
            break;
        case R.id.imageButton_goals_house:
            titleImg.setImageResource(R.drawable.house);
            break;
        case R.id.imageButton_goals_saving:
            titleImg.setImageResource(R.drawable.savings);
            break;
        case R.id.imageButton_goals_travel:
            titleImg.setImageResource(R.drawable.travel);
            break;
        default:
            break;
    }
}

推荐答案

变量 titleImg 可能为空.您应该调试该函数以查看它是否确实是从 setContentValues() 中的第一条语句中找到的.

The variable titleImg is possibly null. You should debug into the function to see if it's actually found from the first statement in setContentValues() or not.

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