小编Luk*_*dge的帖子

我在 Keras/Tensorflow 中创建了一个可用的 CNN 模型，并成功使用 CIFAR-10 和 MNIST 数据集来测试该模型。功能代码如下所示：

import keras
from keras.datasets import cifar10
from keras.utils import to_categorical
from keras.models import Sequential
from keras.layers import Dense, Activation, Dropout, Conv2D, Flatten, MaxPooling2D
from keras.layers.normalization import BatchNormalization

(X_train, y_train), (X_test, y_test) = cifar10.load_data()

#reshape data to fit model
X_train = X_train.reshape(50000,32,32,3)
X_test = X_test.reshape(10000,32,32,3)

y_train = to_categorical(y_train)
y_test = to_categorical(y_test)


# Building the model 

#1st Convolutional Layer
model.add(Conv2D(filters=64, input_shape=(32,32,3), kernel_size=(11,11), strides=(4,4), padding='same'))
model.add(BatchNormalization())
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2,2), strides=(2,2), padding='same'))

#2nd Convolutional Layer
model.add(Conv2D(filters=224, …

我正在尝试在listView中显示数据.我有当前代码尝试获取从myDatabase类传入的数组,然后在我的listView中显示它.

但是我收到了一个错误:

"尝试在空对象引用上调用虚方法'void android.widget.ListView.setAdapter(android.widget.ListAdapter)'".

当我删除listView元素的代码时,我的代码正在主要活动中工作,在我测试的位置我确保传入的数组输出正确(它确实如此).我不确定我错误地发生了这个错误.

MainScreenActivity.java

public class MainScreenActivity extends AppCompatActivity {

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

    // Find View-elements
    Button trackButton = (Button) findViewById(R.id.trackSelectButton);

    // Create click listener for trackSelectionButton
    trackButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {                
            trackInput();

            // Start Track List Activity
            Intent trackScreen = new Intent(v.getContext(), TrackListActivity.class);
            startActivity(trackScreen);
        }
    });        
}

public void trackInput(){

    MyDatabase mDb = new MyDatabase(this);

    String[] tracks = mDb.fetchDatabaseTracks();
    ArrayAdapter<String> trackAdapter =
            new ArrayAdapter<String>(this,
                    android.R.layout.simple_list_item_1,
                    android.R.id.text1, tracks); …