Android：使用ImageView onclick来回更改图像

Question

无效的代码

public void fade(View v){
    ImageView pic1 = (ImageView) findViewById(R.id.pic1);
    ImageView pic2 = (ImageView) findViewById(R.id.pic2);
    pic1.animate().alpha(0f).setDuration(2000);
    pic2.animate().alpha(1f).setDuration(2000);

}

Answer 1

不太确定你要求的是什么，但是如果你想在onClick上来回更改图像，你可以尝试修改我在下面写的代码。

// set a boolean value
private boolean firstImageShown = true;


public void clickFunction(View view) {


    ImageView firstImage = (ImageView) findViewById(R.id.firstImage);

    if ((firstImage != null) && (firstImageShown)) {
        firstImage.setImageResource(R.drawable.sample_image2);
        firstImageShown = false;
    } else {
        if (firstImage != null) firstImage.setImageResource(R.drawable.sample_image1);
        firstImageShown = true;
    }

}

Answer 2

//Suppose you have two images rose_1 and rose_2 and you want to switch back
//and forth between these on a button press.

//Set a static variable 
private static int switcherPressedCount = 2;


//Map the onClick attribute of the button to a function say "switcherPressed".
//"imageView1" is the id attribute of the image which first gets loaded in the 
//app, in this example, it is the attribute of rose_1.
public void switcherPressed(View view){
        ImageView imageView = (ImageView) findViewById(R.id.imageView1);
        if(switcherPressedCount%2 == 0) {
            imageView.setImageResource(R.drawable.rose_2);
            switcherPressedCount = 3; //to avoid reaching maximum int limit.
        }
        else {
            imageView.setImageResource(R.drawable.rose_1);
            switcherPressedCount = 2; //to avoid reaching maximum int limit.
        }
    }