我想做一个按钮来清除文本视图文本。我使用的是Android Studio。
ImageButton ImageButton3;
TextView TextView26;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageButton3.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
TextView.text="";
}
});
您必须实例化文本视图:
ImageButton ImageButton3;
TextView TextView26;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView26 = (TextView) findViewById(R.id.<your text view id>);
ImageButton3.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
TextView26.setText=("");
}
});
我建议您以驼峰大小写命名变量。
此外,如果您可以选择一个更有意义的名称,那就更好了。
您必须先找到两个视图,然后才能在代码中操作它们。
ImageButton imageButton3; //name to clearTextButton?
TextView textView26;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageButton3 = (ImageButton) findViewById(R.id.imgButtonId); //replace it with your true id in your xml
textView26 = (TextView) findViewById(R.id.textViewId);
imageButton3.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
textView26.setText("");
}
});
XML 是文件代码
<com.google.android.material.textview.MaterialTextView
android:id="@+id/tx_demo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Demo World!" />
<com.google.android.material.button.MaterialButton
android:id="@+id/btnClear"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Clear text Button" />
Java是文件代码
txDemo = findViewById(R.id.tx_demo);
btnClear = findViewById(R.id.btnClear);
btnClear.setOnClickListener(v -> {
txDemo.setText("");
});
或
txDemo = findViewById(R.id.tx_demo)
btnClear = findViewById<MaterialButton>(R.id.btnClear)
btnClear.setOnClickListener(View.OnClickListener { v: View? ->
txDemo!!.text = ""
})
您忘记实例化 ImageButton 和 TextView 的视图。
ImageButton ImageButton3;
TextView TextView26;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageButton3 = (ImageButton) findViewById(R.id.myImgBtnId);
TextView26 = (TextView) findViewById(R.id.myTvId);
ImageButton3.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
TextView26.text="";
}
});