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android - 取消触摸时的吐司消息

问题描述

当触摸背景时，我试图让我的 toast 消息过早消失。当触摸屏幕的每个部分时，吐司应该消失......我知道方法是 .cancel 但我无法正确使用它..这是我尝试过的：

我尝试使用 .setontouchlistener 方法，但它不起作用......我是 android 开发的新手，所以如果有一个示例代码可以学习......我会告诉你我的代码，就是这样：

public class MainActivity extends AppCompatActivity {
private LayoutInflater layoutInflater;
private RelativeLayout relalayout
private LinearLayout linelayout;
private ScrollView scrollayout;
public Toast toast;
private ImageView backgroundimg;

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_activitymain);
    Bundle extradata1 = getIntent().getExtras();
    String textString = extradata1.getString("ImportedData");
    TextView mytext = (TextView) findViewById(R.id.text);
    relalayout = (RelativeLayout) findViewById(R.id.relalayout);
    linelayout = (LinearLayout) findViewById(R.id.linelayout);
    scrollayout = (ScrollView) findViewById(R.id.scrolllayout);
    backgroundimg = (ImageView) findViewById(R.id.imageView2);
    toast = new Toast(this);

 if (textString.equals("firstimported")) {

        String mytxt = "";
        StringBuffer sbuffer = new StringBuffer();
        InputStream is = this.getResources().openRawResource(R.raw.firsttext);
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));


        try {

            while ((mytxt = reader.readLine()) != null) {
                sbuffer.append(mytxt + "\n");

            }

            mytext.setText(sbuffer);
            is.close();


        } catch (Exception e) {
            e.printStackTrace();
        }
        String text = sbuffer.toString();
        SpannableString ss = new SpannableString(text);

ClickableSpan clickspan1 = new ClickableSpan() {
@Override
public void onClick(View widget) {
    Toast toast = Toast.makeText(MainActivity.this, "this is the toast",
    Toast.LENGTH_SHORT);
    toast.show();}
    @Override
    public void updateDrawState(TextPaint ds) {

        super.updateDrawState(ds);
        ds.setColor(Color.WHITE);
        ds.setUnderlineText(false);}
    };

    scrollayout.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        toast.cancel();
        return false;
    }
});
ss.setSpan(clickspan1, 52, 53, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);

mytext.setText(ss);
        mytext.setMovementMethod(LinkMovementMethod.getInstance());

}
}

public void onBackPressed() {
    Intent intent = new Intent(MainActivity.this, OtherActivity.class);
    startActivity(intent);
    finish();
}

当我触摸屏幕时活动崩溃..所以它不起作用。

标签： androidandroid-toast

解决方案

您必须Toast在活动的变量上声明对象

private Toast toast;

然后在你的 onClick 方法上初始化它：

toast = Toast.makeText(MainActivity.this, "this is the toast",Toast.LENGTH_SHORT);
toast.show();

此外，onTouch您应该检查 toast 对象是否为空：

if(toast != null){
   toast.cancel();
}

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