Question

我在这行收到错误：

final Button addBtn = (Button) findViewById(R.id.btnAdd);

我的代码：

package com.example.avivyaacobi.contactmanager;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;
import android.widget.TabHost;

public class MainActivity extends Activity {

    EditText nameTxt, phoneTxt, emailTxt, addressTxt;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        nameTxt = (EditText) findViewById(R.id.txtName);
        phoneTxt = (EditText) findViewById(R.id.txtPhone);
        emailTxt = (EditText) findViewById(R.id.txtEmail);
        addressTxt = (EditText) findViewById(R.id.txtAddress);
        TabHost tabHost = (TabHost) findViewById(R.id.tabHost);

        tabHost.setup();

        TabHost.TabSpec tabSpec= tabHost.newTabSpec("creator");
        tabSpec.setContent(R.id.tabCreator);
        tabSpec.setIndicator("Creator");
        tabHost.addTab(tabSpec);

        tabSpec= tabHost.newTabSpec("list");
        tabSpec.setContent(R.id.tabContactList);
        tabSpec.setIndicator("List");
        tabHost.addTab(tabSpec);

        final Button addBtn = (Button) findViewById(R.id.btnAdd);

        nameTxt.addTextChangedListener(new TextWatcher() {
           @Override
           public void beforeTextChanged(CharSequence s, int start, int count, int after) {

           }

           @Override
           public void onTextChanged(CharSequence s, int start, int before, int count) {
            addBtn.setEnabled(!nameTxt.getText().toString().trim().isEmpty());

           }

           @Override
           public void afterTextChanged(Editable s) {

           }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

我有功能按钮：

package com.example.avivyaacobi.contactmanager;

/**
 * Created by AvivYaacobi on 10/1/15.
 */
public class Button {
    private boolean enable;

    public void setEnabled(boolean enabled) {
        this.enable = enabled;
    }
}

我不得不说我是这个工具（Android Studio）和Java的新手，我不知道是什么问题。

Answer 1

您正在尝试将小部件（Button）强制转换为自定义类（也称为Button）。将自定义类重命名为更能说明其功能的内容，或者使用按钮小部件的完整包标识符，如下所示。

 final android.widget.Button addBtn = (android.widget.Button) findViewById(R.id.btnAdd);

无法投射＆＃39; android.view.View＆＃39; to＆＃39; com.example.avivyaacobi.contactmanager.Button＆＃39;

1 个答案: