Java 如何淡入初始化为0 alpha的textview

fade_in.xml：

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" android:interpolator="@android:anim/linear_interpolator">
    <alpha
        android:duration="500"
        android:fromAlpha="0.0"
        android:toAlpha="1.0">
    </alpha>
</set>

基于布尔onClick的一个或另一个淡入淡出：

    Button commitChanges = findViewById(R.id.commitChanges);
    commitChanges.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view){
            EditText iai = findViewById(R.id.agentIdInput); //iai = i_nput a_gent i_d
            agentIdInputString = iai.getText().toString();

        incompleteForm = agentIdInputString.equals("");//returns True if there is no input
        //please disregard my lack of an input filter

        if (incompleteForm){
            TextView commitWarning = findViewById(R.id.commitChangesToastContainerWarning);
            Animation aniFadeIn = AnimationUtils.loadAnimation(getApplicationContext(),R.anim.fade_in);
            commitWarning.startAnimation(aniFadeIn);
        } else {
        TextView commitSuccess = findViewById(R.id.commitChangesToastContainer);
        Animation aniFadeIn = AnimationUtils.loadAnimation(getApplicationContext(),R.anim.fade_in);
        commitSuccess.startAnimation(aniFadeIn);
    };

我这样做的原因是因为我想基本上用textview创建我自己的“Toast”容器，我可以将它放在一个非常特定的位置，并相应地格式化textview，并将自制的Toast限制在我的布局中

这是我的应用程序蓝图的图片。您可以看到我的edittext、基于布尔值淡入的两个对象以及我的提交按钮。如果你需要更多的信息，请告诉我

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.settings_upright);

    //sets these textviews to invisible for later use. DOES NOT LET ME EDIT THE ALPHA VALUE
    TextView commitWarning = findViewById(R.id.commitChangesToastContainerWarning);
    TextView commitSuccess = findViewById(R.id.commitChangesToastContainer);
    commitWarning.setAlpha(0f);
    commitSuccess.setAlpha(0f);

    Button commitChanges = findViewById(R.id.commitChanges);
    commitChanges.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view){
            EditText iai = findViewById(R.id.agentIdInput); //iai = i_nput a_gent i_d
            agentIdInputString = iai.getText().toString();

        incompleteForm = agentIdInputString.equals("");//returns True if there is no input
        //please disregard my lack of an input filter

        if (incompleteForm){
            TextView commitWarning = findViewById(R.id.commitChangesToastContainerWarning);
            Animation aniFadeIn = AnimationUtils.loadAnimation(getApplicationContext(),R.anim.fade_in);
            commitWarning.startAnimation(aniFadeIn);
        } else {
        TextView commitSuccess = findViewById(R.id.commitChangesToastContainer);
        Animation aniFadeIn = AnimationUtils.loadAnimation(getApplicationContext(),R.anim.fade_in);
        commitSuccess.startAnimation(aniFadeIn);
    };