Android逐字符显示文字动画

Question

任何人都知道执行动画的任何有效方法就是逐个字符地显示文本吗？喜欢:

T
Th
Thi
This
This i
This is
...

等等。

谢谢!

Answer 1

这可能不是最优雅的解决方案，但最简单的可能是 TextView 的快速子类，它带有一个 Handler，它会不时更新文本，直到完成序列显示:

public class Typewriter extends TextView {

    private CharSequence mText;
    private int mIndex;
    private long mDelay = 500; //Default 500ms delay


    public Typewriter(Context context) {
        super(context);
    }

    public Typewriter(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    private Handler mHandler = new Handler();
    private Runnable characterAdder = new Runnable() {
        @Override
        public void run() {
            setText(mText.subSequence(0, mIndex++));
            if(mIndex <= mText.length()) {
                mHandler.postDelayed(characterAdder, mDelay);
            }
        }
    };

    public void animateText(CharSequence text) {
        mText = text;
        mIndex = 0;

        setText("");
        mHandler.removeCallbacks(characterAdder);
        mHandler.postDelayed(characterAdder, mDelay);
    }

    public void setCharacterDelay(long millis) {
        mDelay = millis;
    }
}

然后你可以像这样在 Activity 中使用它:

public class MyActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Typewriter writer = new Typewriter(this);
        setContentView(writer);

        //Add a character every 150ms
        writer.setCharacterDelay(150);
        writer.animateText("Sample String");
    }
}

如果您想要添加每个字母的动画效果，也许可以查看子类 TextSwitcher。

希望有帮助!